High serum levels of leucine-rich α-2 glycoprotein 1 (LRG-1) are associated with poor survival in patients with early breast cancer

BACKGROUND

Leucine-rich α-2 glycoprotein 1 (LRG-1) is a secreted glycoprotein that is mainly produced in the liver. Elevated levels of LRG-1 are found in a multitude of pathological conditions including eye diseases, diabetes, infections, autoimmune diseases, and cancer. In patients with early breast cancer (BC), high intratumoral LRG-1 protein expression levels are associated with reduced survival. In this study, we assessed serum levels of LRG-1 in patients with early BC and investigated its correlation with the presence of disseminated tumor cells (DTCs) in the bone marrow and survival outcomes.

METHODS

Serum LRG-1 levels of 509 BC patients were determined using ELISA and DTCs were assessed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. We stratified LRG-1 levels according to selected clinical parameters. Using the log-rank (Mantel-Cox) test and multivariate Cox regression analysis, Kaplan-Meier survival curves and prognostic relevance were assessed.

RESULTS

Mean serum levels of LRG-1 were 29.70 ± 8.67 µg/ml. Age was positively correlated with LRG-1 expression (r = 0.19; p < 0.0001) and significantly higher LRG-1 levels were found in patients over 60 years compared to younger ones (30.49 ± 8.63 µg/ml vs. 28.85 ± 8.63 µg/ml; p = 0.011) and in postmenopausal patients compared to premenopausal patients (30.15 ± 8.34 µg/ml vs. 26.936.94 µg/ml; p = 0.002). Patients with no DTCs showed significantly elevated LRG-1 levels compared to the DTC-positive group (30.51 ± 8.69 µg/ml vs. 28.51 ± 8.54 µg/ml; p = 0.004). Overall and BC-specific survival was significantly lower in patients with high serum LRG-1 levels (above a cut-off of 33.63 µg/ml) compared to patients with lower LRG-1 levels during a mean follow-up of 8.5 years (24.8% vs. 11.1% BC-specific death; p = 0.0003; odds ratio 2.63, 95%CI: 1.56-4.36). Multivariate analyses revealed that LRG-1 is an independent prognostic marker for BC-specific survival (p = 0.001; hazard ratio 2.61).

CONCLUSIONS

This study highlights the potential of LRG-1 as an independent prognostic biomarker in patients with early BC.

Ratios of monocytes and neutrophils to lymphocytes in the blood predict benefit of CDK4/6 inhibitor treatment in metastatic breast cancer

Biomarkers to identify metastatic breast cancer (mBC) patients resistant to CDK4/6 inhibition (CDK4/6i) are currently missing. We evaluated the usefulness of the monocyte-to-lymphocyte ratio (MLR), the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) as predictive markers for de novo resistance to CDK4/6i. Various blood cell counts and MLR, NLR, PLR were recorded before treatment initiation (baseline) and four weeks later from 97 mBC patients receiving endocrine therapy (ET) alone or in combination with CDK4/6i. Binary blood cell count/ratios (mean = cut-off) were related to outcome using Cox regression. High MLR (p = 0.001) and high NLR (p = 0.01) at baseline significantly correlated with a shorter progression-free survival (PFS) in the CDK4/6i cohort, independent of any other clinical parameter as determined by multivariate Cox regression. Both, high MLR (p = 0.008) and high NLR (p = 0.043) as well as a decrease in PLR after four weeks of CDK4/6i first line treatment (p = 0.01) indicated a shorter overall survival. Moreover, decreasing PLR (p = 0.043) and increasing mean corpuscular volume (MCV; p = 0.011) within the first cycle of CDK4/6i correlated with a shorter PFS and decreasing MLR (p = 0.039) within the first cycle of first-line CDK4/6i was also correlated with shorter PFS. In summary, easily assessable blood cell parameter were shown to have predictive, monitoring and prognostic value and thus, could, in future, be used for individualized CDK4/6i therapy management. Most importantly, the imbalance of NLR and MLR at baseline might serve as predictive marker for de novo resistance to CDK4/6i in mBC patients.

The Diversity of Liquid Biopsies and Their Potential in Breast Cancer Management

Analyzing blood as a so-called liquid biopsy in breast cancer (BC) patients has the potential to adapt therapy management. Circulating tumor cells (CTCs), extracellular vesicles (EVs), cell-free DNA (cfDNA) and other blood components mirror the tumoral heterogeneity and could support a range of clinical decisions. Multi-cancer early detection tests utilizing blood are advancing but are not part of any clinical routine yet. Liquid biopsy analysis in the course of neoadjuvant therapy has potential for therapy (de)escalation.Minimal residual disease detection via serial cfDNA analysis is currently on its way. The prognostic value of blood analytes in early and metastatic BC is undisputable, but the value of these prognostic biomarkers for clinical management is controversial. An interventional trial confirmed a significant outcome benefit when therapy was changed in case of newly emerging cfDNA mutations under treatment and thus showed the clinical utility of cfDNA analysis for therapy monitoring. The analysis of PIK3CA or ESR1 variants in plasma of metastatic BC patients to prescribe targeted therapy with alpesilib or elacestrant has already arrived in clinical practice with FDA-approved tests available and is recommended by ASCO. The translation of more liquid biopsy applications into clinical practice is still pending due to a lack of knowledge of the analytes' biology, lack of standards and difficulties in proving clinical utility.

Elevated sHLA-G plasma levels post chemotherapy combined with ILT-2 rs10416697C allele status of the sHLA-G-related receptor predict poorest disease outcome in early triple-negative breast cancer patients

Introduction

Triple negative breast cancer (TNBC) shows an aggressive growing and spreading behavior and has limited treatment options, often leading to inferior disease outcome. Therefore, surrogate markers are urgently needed to identify patients at high risk of recurrence and more importantly, to identify additional therapeutic targets enabling further treatment options. Based on the key role of the non-classical human leukocyte antigen G (HLA-G) and its related receptor immunoglobulin-like transcript receptor-2 (ILT-2) in immune evasion mechanisms of tumors, members of this ligand-receptor axis appear to be promising tool for both, defining risk groups and potential therapeutic targets.

Materials and methods

To follow this, sHLA-G levels before and after chemotherapy (CT), HLA-G 3' UTR haplotypes, and allele variations rs10416697 at the distal gene promoter region of ILT-2 were defined in healthy female controls and early TNBC patients. The results obtained were associated with clinical status, presence of circulating tumor cell (CTC) subtypes, and disease outcome of patients in terms of progression-free or overall survival.

Results

sHLA-G plasma levels were increased in TNBC patients post-CT compared to levels of patients pre-CT or controls. High post-CT sHLA-G levels were associated with the development of distant metastases, the presence of ERCC1 or PIK3CA-CTC subtypes post-CT, and poorer disease outcome in uni- or multivariate analysis. HLA-G 3' UTR genotypes did not influence disease outcome but ILT-2 rs10416697C allele was associated with AURKA-positive CTC and with adverse disease outcome by uni- and multivariate analysis. The prognostic value of the combined risk factors (high sHLA-G levels post-CT and ILT-2 rs10416697C allele carrier status) was an even better independent indicator for disease outcome in TNBC than the lymph nodal status pre-CT. This combination allowed the identification of patients with high risk of early progression/death with positive nodal status pre-CT or with non-pathological complete therapy response.

Conclusion

The results of this study highlight for the first time that the combination of high levels of sHLA-G post-CT with ILT-2 rs10416697C allele receptor status is a promising tool for the risk assessment of TNBC patients and support the concept to use HLA-G/ILT-2 ligand-receptor axis as therapeutic targets.

Abstract 6693: Stability of urinary cell-free DNA and detection of T790M variant

Background: The so-called “liquid biopsy” has become a powerful tool for cancer research in the recent years, with circulating cell-free DNA (cfDNA) that originates from tumors as one of the most promising analytes. In contrast to plasma derived cfDNA, only a few studies were performed investigating urinary cfDNA. One reason might be quick degradation and hence relatively low concentrations of urinary cfDNA. This study focused on examining the stability of cfDNA in urine using different ways of preservation under various storage conditions.

Methodology: To mimic patient samples, a pool of healthy male and female urine donors was spiked with a synthetic cfDNA reference standard (fragment size 170 bp) containing the T790M mutation in the EGFR gene and preserved with three different buffers and no buffer over four different storage periods (0; 4; 12; 24 h) at room temperature vs. fridge. Preservatives used were the Urinary Analyte Stabilizer (UAS, Novosanis), the Urine Conditioning Buffer (UCB, Zymo) and a self-prepared buffer called “AlloU”. The cfDNA was extracted with the QIAamp MinElute ccfDNA Mini Kit (Qiagen) and the concentration measured with the Qubit™ 4 fluorometer (Thermo Fisher Scientific). Droplet digital PCR (ddPCR) was used for detection and quantification of the T790M mutation (Bio-Rad)

Results: From the model samples with no preservation buffer, almost no spiked cfDNA could be recovered and the T790M variant could not be detected using ddPCR, indicating that without preservation cfDNA was degraded below the detection limit by the nucleases present in urine. The most effective stabilizing buffer over all storage periods and at room as well as fridge temperature was the UAS, resulting in accurate detection of the T790M variant using ddPCR.

Conclusion: From a technical point of view, urinary cfDNA might be useful for non-invasive disease monitoring when the samples are stabilized and stored adequately during clinical routine.

Citation Format: Carolin Münch, Saikal Shamkeeva, Mitja Heinemann, Berend Isermann, Sabine Kasimir-Bauer, Bahriye Aktas, Ivonne Nel. Stability of urinary cell-free DNA and detection of T790M variant. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6693.

Abstract 2140: DNA damage response in circulating tumor cells shows predictive value for metastatic breast cancer patients receiving CDK4/6 inhibitors

Background: Resistance to CDK4/6 inhibitors (CDK4/6i), like Palbociclib and Ribociclib, plus endocrine therapy (TX) is an omnipresent topic for metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients (pts). Circulating tumor cells (CTCs) represent the oncogenic heterogeneity in real time. Here, we aim to identify markers of resistance to CDK4/6i by mRNA profiling of CTCs.

Methods: Blood of 90 HR+/HER2-MBC pts drawn before CDK4/6i plus endocrine TX (baseline: n=57 pts first line; n=33 second or more line pts), 19 HR+/HER2-MBC pts receiving endocrine monoTX (control group) and matched samples of 78/62 of these 109 pts after six months of TX/at progression (PD) were analyzed. Isolation of CTCs was conducted using the AdnaTest EMT2/StemCell Select. Expression profiling was conducted with preamplified cDNA utilizing QuantiNova LNA Probe assays targeting 25 genes. qPCR data were normalized to CD45 and data of 20 healthy female donors. Consumables: QIAGEN, Germany. Only results with Benjamini Hochberg corrected p&lt;0.05 in univariate Cox regression and multivariate Cox regression with non-adjusted p&lt;0.05 are demonstrated.

Results: At baseline, in pts treated with CDK4/6i in the first line, CETN2 (HR 3.6)/MLH3 (HR 4)/E2F1 (HR 5.3) overexpression signals in CTCs correlated significantly with shorter progression-free survival (PFS) and shorter overall survival [(baseline to death, OS) (HR 8.3/HR 4.9/HR 3.8)], whereas ESR1 signals correlated with a shorter OS (HR 4.4). After six months of TX, in CDK4/6i treated pts, CXCR4 and CETN2 signals correlated with a shorter PFS and the signal dynamics from baseline to six months of CXCR4, CETN2 and PCNA also correlated with a shorter PFS. At PD, STAT1 signals were identified as potential Ribociclib specific resistance markers and Hippo pathway inhibition as a potential new approach for postCDK4/6i TX, because TEAD2 and WWTR1 correlated with shorter remaining time to death.

Conclusion: We identified overexpression of transcripts involved in DNA damage response mechanisms (CETN2, MLH3 and/or PCNA) at baseline to have predictive and/or prognostic value in first line CDK4/6i treated pts while signal dynamics of CETN2 and PCNA to six months of TX could serve as monitoring marker in these pts. Currently, further longitudinal blood sampling over the course of treatment is underway to give a deeper insight in resistance development under CDK4/6i treatment.

Citation Format: Corinna Keup, Charlotte Gruber, Stefanos Ioannis Moukas, Mitra Tewes, Hans-Christian Kolberg, Rainer Kimmig, Sabine Kasimir-Bauer. DNA damage response in circulating tumor cells shows predictive value for metastatic breast cancer patients receiving CDK4/6 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2140.

Correlation between Imaging Markers Derived from PET/MRI and Invasive Acquired Biomarkers in Newly Diagnosed Breast Cancer

PURPOSE

Evaluate the diagnostic potential of [¹⁸F]FDG-PET/MRI data compared with invasive acquired biomarkers in newly diagnosed early breast cancer (BC).

METHODS

Altogether 169 women with newly diagnosed BC were included. All underwent a breast- and whole-body [¹⁸F]FDG-PET/MRI for initial staging. A tumor-adapted volume of interest was placed in the primaries and defined bone regions on each standard uptake value (SUV)/apparent diffusion coefficient (ADC) dataset. Immunohistochemical markers, molecular subtype, tumor grading, and disseminated tumor cells (DTCs) of each patient were assessed after ultrasound-guided biopsy of the primaries and bone marrow (BM) aspiration. Correlation analysis and group comparisons were assessed.

RESULTS

A significant inverse correlation of estrogen-receptor (ER) expression and progesterone-receptor (PR) expression towards SUV_max was found (ER: r = 0.27, p < 0.01; PR: r = 0.19, p < 0.05). HER2-receptor expression showed no significant correlation towards SUV and ADC values. A significant positive correlation between Ki67 and SUVmax and SUV_mean (r = 0.42 p < 0.01; r = 0.19 p < 0.05) was shown. Tumor grading significantly correlated with SUV_max and SUV_mean (ρ = 0.36 and ρ = 0.39, both p's < 0.01). There were no group differences between SUV/ADC values of DTC-positive/-negative patients.

CONCLUSIONS

[¹⁸F]FDG-PET/MRI may give a first impression of BC-receptor status and BC-tumor biology during initial staging by measuring glucose metabolism but cannot distinguish between DTC-positive/-negative patients and replace biopsy.

Programmed death receptor ligand-2 (PD-L2) bearing extracellular vesicles as a new biomarker to identify early triple-negative breast cancer patients at high risk for relapse

PURPOSE

Based on the tumor-promoting features of extracellular vesicles (EV) and PD-L1/2-bearing EV subpopulations (PD-L1/2_EV), we evaluated their potential as surrogate markers for disease progression or eligibility criteria for PD-1 immune checkpoint inhibition (ICI) approaches in early triple-negative breast cancer (TNBC).

METHODS

After enrichment of EV from plasma samples of 56 patients before and 50 after chemotherapy (CT), we determined levels of EV particle number and PD-L1/2_EV by nanoparticle tracking analysis or ELISA and associated the results with clinical status/outcome and the presence of distinct circulating tumor cells (CTC) subpopulations.

RESULTS

Compared to healthy controls, patients had a tenfold higher EV concentration and significantly elevated PD L2_EV but not PD L1_EV levels. The most important clinical implications were found for PD-L2_EV. High PD-L2_EV levels were associated with a significantly reduced 3-year progression-free and overall survival (PFS and OS). A loss of PD-L2_EV after CT was significantly more prominent in patients achieving pathological complete response (pCR). Increased pre-CT PD-L2_EV levels were found in patients having NOTCH1-positive or ERBB3-positive CTC. The presence of ERBB3-positive CTC combined with high pre-CT PD-L2_EV resulted in a shorter PFS.

CONCLUSION

This study highlights PD L2_EV as a promising biomarker for risk assessment of TNBC patients and represents the basic for additional studies introducing PD-L2_EV as an eligibility criterion for PD-1 ICI approaches.

Abstract PD11-03: PD11-03 Comparison of a mono Atezolizumab window followed by Atezolizumab and chemotherapy with Atezolizumab and chemotherapy in triple negative breast cancer – an interim analysis of the adaptive randomized neoadjuvant trial NeoMono

Introduction: Improvement of systemic treatment of TNBC represents an unmet medical need. Targeted therapy of regulatory immune pathways has become an important option in the treatment of many malignant diseases including breast cancer. Neodjuvant trials combining chemotherapy and checkpoint inhibitors (KEYNOTE-522 and IMpassion031) have demonstrated a meaningful benefit regarding pathological complete remission (pCR) for the addition of PD-1- or PD-L1-inhibitors to chemotherapy in patients with TNBC. In the KEYNOTE-522 trial, the addition of an immune checkpoint inhibitor (ICI) to neoadjuvant chemotherapy also had a beneficial impact on event-free survival even in patients who did not achieve a pCR. Of note, in the neoadjuvant GeparNuevo trial only those patients with TNBC who received a 2-week checkpoint inhibitor monotherapy window before the start of neoadjuvant chemotherapy in combination with checkpoint inhibition, achieved a significant pCR benefit from the addition of the PD-1 inhibitor Durvalumab to neoadjuvant chemotherapy alone. Methods: NeoMono is a phase 2 randomized multicenter trial recruiting male and female patients with primary TNBC (defined as ER/PR &lt; 10% and HER2 negative). Neoadjuvant treatment in Arm A and B consists of Atezolizumab 1200 mg every 3 weeks in addition to neoadjuvant chemotherapy (i.e., 12 x Carboplatin and Paclitaxel q1w followed by Epirubicin and Cyclophosphamide q3w). Combination therapy in arm A is preceded by an Atezolizumab monotherapy window (i.e., 840 mg Atezolizumab once two weeks prior to initiation of combination therapy). Study goals are to compare the efficacy of neoadjuvant chemotherapy with Atezolizumab with and without an Atezolizumab two-week monotherapy window (primary endpoint: pCR) and the identification of biomarkers predicting (early) response to or resistance against Atezolizumab. The extensive translational program of the neoMono trial aims at identifying these biomarkers on tumor and patient level through analysis of sequential tissue and liquid biopsies. The NeoMono statistical design adapts the idea of a proof-of-concept trial and uses Bayesian posterior and predictive probabilities for inference about the primary hypothesis. Up to four planned efficacy interim analyses provide decision points for early stopping for success or futility. The expected maximum number of patients to be recruited is 458. Results: The predefined number of 50 patients in each arm being evaluable for the primary endpoint pCR has been reached and the results of the first planned interim analysis will be presented at the meeting. Conclusion: The addition of an ICI to state of the art neoadjuvant chemotherapy has recently been established as a new standard of care in TNBC. NeoMono has the potential to answer the question if the beneficial effect of the ICI can be increased by a chemotherapy free ICI monotherapy window prior to a combination with neoadjuvant chemotherapy.

Citation Format: Hans-Christian Kolberg, Johannes Schumacher, Ramona Erber, Michael Braun, Bernhard Heinrich, Oliver Hoffmann, Peter A. Fasching, Georg Kunz, Michael P. Lux, Christian Schem, Eva-Maria Grischke, Mustafa Deryal, Kristina Lübbe, Arndt Hartmann, Sabine Kasimir-Bauer, Cornelia Kolberg-Liedtke. PD11-03 Comparison of a mono Atezolizumab window followed by Atezolizumab and chemotherapy with Atezolizumab and chemotherapy in triple negative breast cancer – an interim analysis of the adaptive randomized neoadjuvant trial NeoMono [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD11-03.

Abstract P5-02-25: Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition

Background: De novo resistance defined as progression within six months and acquired resistance are one of the major problems in the subset of metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients without visceral crisis receiving CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy (TX). Here, we aim to identify predictive and monitoring markers of CDK4/6i resistance by conducting transcriptional profiling of circulating tumor cells (CTCs) that represent a real-time snapshot of the heterogeneity. Methods: Blood of (A) 60 HR+/HER2- MBC patients drawn at baseline of Palbociclib plus endocrine TX (TX as first line n=31, second or more lines n=29), (B) 19 HR+/HER2- MBC patients drawn before the initiation of endocrine monoTX (control) and matched blood samples of these patients after six months under TX (n=72) and at the time of progression (n=42) were analyzed. To enlarge the global CDK4/6i cohort at baseline, blood of (C) 32 patients before the initiation of Ribociclib plus endocrine TX was also drawn. Patients with progression within six months were defined as non-responders. Isolation of CTCs was conducted using positive immunomagnetic selection (AdnaTest EMT2/StemCell Select) and preamplified cDNA was analyzed by a multimarker qPCR panel utilizing QuantiNova LNA Probe assays targeting 25 genes involved in the DNA damage -, MAPK -, STAT -, Hippo – pathway or cell cycle, chemokine sensing, multidrug resistance and cell adhesion. qPCR data was normalized to CD45 and data of 20 healthy female donor controls to identify BC CTC specific overexpression signals with a specificity of &gt;90% for all targets. Consumables: QIAGEN, Germany. Statistical analysis included log-rank testing and univariate Cox regression. Results: For first line CDK4/6i treated patients at baseline, CETN2 and E2F1 signals correlated significantly with worse progression-free survival (PFS) while CETN2 signals also related significantly to non-response. Furthermore, CETN2 and PCNA signals were significantly associated with worse overall survival (OS). Analyzing the Palbociclib cohort after six months of TX, PCNA signals correlated significantly with a decreased PFS while EpCAM signals showed a significant association with OS. In addition, CETN2, CXCR4, EpCAM, MLH3, WWTR1 signals after six months were shown to correlate significantly with a decreased OS and PFS and MAPK1 signals were only found in the non-responders. While non-response was related to appearing (from baseline to six months under TX) ABCC2, JUN and MAPK1 signals, disappearing ABCC2 signals were only found in the responders. Dynamics of ABCC2, CXCR4, EpCAM, JUN, MAPK1, MLH3, STAT1 and WWTR1 signals from baseline to six months under TX correlated significantly with OS and CXCR4 signal dynamics significantly with a worse PFS. At the time of progression, the presence of E2F1, JUN, MAPK1 and STAT1 signals correlated significantly with a decreased OS and in comparison to baseline analysis, the prevalence of ABCC2, EpCAM, E2F1, CETN2 and CXCR4 signals increased. Conclusion: CTC overexpression signals at baseline of targets involved in the cell cycle (CETN2 and E2F1) might be predictive markers for de novo resistance to CDK4/6i as first line TX, while ABCC2 (multidrug resistance), EpCAM (cell adhesion), E2F1, CETN2 and CXCR4 (chemokine sensing) signals could indicate acquired resistance to Palbociclib. In case of disease progression, E2F1, JUN (cell cycle) and targets of the MAPK- and STAT- pathway could be relevant targets for therapeutic strategies beyond Palbociclib TX. Monitoring and prognostic value was shown for single and repeated measurement of signals under TX in genes involved in resistance, cell cycle progression, DNA damage response (MLH3, PCNA), chemokine sensing, cell adhesion and the MAPK-, STAT- and Hippo (WWTR1) pathway.

Citation Format: Sabine Kasimir-Bauer, Charlotte Gruber, Stefanos Moukas, Mitra Tewes, Hans-Christian Kolberg, Rainer Kimmig, Corinna Keup. Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-25.

Detection of ESR1 Mutations in Primary Tumors and Plasma Cell-Free DNA in High-Grade Serous Ovarian Carcinoma Patients

Simple Summary

In the present study we evaluated the frequency and the clinical relevance of ESR1 mutations in high-grade serous ovarian cancer (HGSOC). Drop-off droplet digital PCR (ddPCR) was first used to screen for ESR1 mutations in primary tumors (formalin-fixed paraffin-embedded, FFPEs) from HGSOC patients and plasma cell-free DNA (cfDNA) samples from advanced and metastatic ovarian cancer patients. We further used the recently developed ESR1-NAPA assay to detect individual ESR1 mutations in drop-off ddPCR-positive samples. We report for the first time the presence of ESR1 mutations in 15% of FFPEs and in 13.8% of plasma cfDNA samples from advanced and metastatic ovarian cancer patients.

Abstract

ESR1 mutations have been recently associated with resistance to endocrine therapy in metastatic breast cancer and their detection has led to the development and current evaluation of novel, highly promising therapeutic strategies. In ovarian cancer there have been just a few reports on the presence of ESR1 mutations. The aim of our study was to evaluate the frequency and the clinical relevance of ESR1 mutations in high-grade serous ovarian cancer (HGSOC). Drop-off droplet digital PCR (ddPCR) was first used to screen for ESR1 mutations in 60 primary tumors (FFPEs) from HGSOC patients and in 80 plasma cell-free DNA (cfDNA) samples from advanced and metastatic ovarian cancer patients. We further used our recently developed ESR1-NAPA assay to identify individual ESR1 mutations in drop-off ddPCR-positive samples. We report for the first time the presence of ESR1 mutations in 15% of FFPEs and in 13.8% of plasma cfDNA samples from advanced and metastatic ovarian cancer patients. To define the clinical significance of this finding, our results should be further validated in a large and well-defined cohort of ovarian cancer patients.

Abstract 6256: Longitudinal transcriptional profiling of CTCs in metastatic breast cancer patients receiving CDK4/6 inhibitors to predict response

Background: CDK4/6 inhibitors recently became the first choice for treatment of metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients (pts). However, predictive markers are missing. Circulating tumor cells (CTCs) represent the heterogeneous disease in real time. Here, we aim to identify resistance markers to CDK4/6 inhibitors by mRNA profiling of CTCs.

Methods: Blood of 51 HR+/HER2-MBC pts drawn at baseline, before endocrine and Palbociclib treatment (n=22 pts first line; n=29 pts second line or more), blood of 19 HR+/HER2-MBC pts drawn at baseline of endocrine monotherapy (control group; n=6 pts first line; n=13 pts second line or more), as well as blood samples of 34 of these 70 pts after six months under treatment were analyzed. Pts with stable disease within the first six months of treatment were defined as responders. Isolation of CTCs was conducted using AdnaTest EMT2/StemCell Select. Preamplified cDNA was analyzed by a new multimarker qPCR panel utilizing QuantiNova LNA Probe assays targeting 25 genes. qPCR data were normalized to CD45 and data of 20 healthy female donors. Consumables: QIAGEN, Germany. Statistical analysis was conducted via log-rank test and fisher’s exact test.

Results: EpCAM, PCNA, STAT1 and YAP1 signals at baseline showed a higher prevalence in non-responders compared to responders in the Palbociclib treated cohort, while CXCR4 signals were only detected in responders. WWTR1 signals significantly correlated with reduced PFS (p=0.001) and OS (p=0.043) in all first line treated pts. YAP1 signals significantly correlated with decreased PFS (p=0.018) and OS (p=0.000) in the first line Palbociclib treated cohort and significantly correlated with decreased PFS in all first line treated pts, too (p=0.044). After six months of treatment, CDK2 signals were significantly more common in non-responders compared to responders in the Palbociclib treated cohort (p&lt;0.05) while TEAD2 (p=0.014) and CDK2 (p=0.046) signals significantly correlated with worse OS in the Palbociclib treated group, but not in the control group. We identified a higher percentage of disappearing signals in responders than in non-responders and the percentage of newly appearing signals was higher in non-responders compared to responders. The dynamics of TEAD2 (p=0.036) and MLH3 (p=0.000) signals significantly correlated with OS in the Palbociclib treated cohort, but not in the control cohort.

Conclusion: Preliminary results of the transcriptional profiling of CTCs indicate that WWTR1 and YAP1 signals at baseline might be predictive markers that do not favor Palbociclib treatment. CDK2 signals after six months or the dynamics of TEAD2 and MLH3 signals might be suitable as monitoring markers. To validate the findings, we plan to analyze additional blood samples drawn at disease progression under CDK4/6 inhibition and expand our cohort.

Citation Format: Corinna Keup, Charlotte Gruber, Oliver Hoffmann, Rainer Kimmig, Sabine Kasimir-Bauer. Longitudinal transcriptional profiling of CTCs in metastatic breast cancer patients receiving CDK4/6 inhibitors to predict response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6256.

Systematic Evaluation of HLA-G 3'Untranslated Region Variants in Locally Advanced, Non-Metastatic Breast Cancer Patients: UTR-1, 2 or UTR-4 are Predictors for Therapy and Disease Outcome

Despite major improvements in diagnostics and therapy in early as well as in locally advanced breast cancer (LABC), metastatic relapse occurs in about 20% of patients, often explained by early micro-metastatic spread into bone marrow by disseminated tumor cells (DTC). Although neoadjuvant chemotherapy (NACT) has been a successful tool to improve overall survival (OS), there is growing evidence that various environmental factors like the non-classical human leukocyte antigen-G (HLA-G) promotes cancer invasiveness and metastatic progression. HLA-G expression is associated with regulatory elements targeting certain single-nucleotide polymorphisms (SNP) in the HLA-G 3’ untranslated region (UTR), which arrange as haplotypes. Here, we systematically evaluated the impact of HLA-G 3’UTR polymorphisms on disease status, on the presence of DTC, on soluble HLA-G levels, and on therapy and disease outcome in non-metastatic LABC patients. Although haplotype frequencies were similar in patients (n = 142) and controls (n = 204), univariate analysis revealed that the UTR-7 haplotype was related to patients with low tumor burden, whereas UTR-4 was associated with tumor sizes >T1. Furthermore, UTR-4 was associated with the presence of DTC, but UTR-3 and UTR-7 were related to absence of DTC. Additionally, increased levels of soluble HLA-G molecules were found in patients carrying UTR-7. Regarding therapy and disease outcome, univariate and multivariate analysis highlighted UTR-1 or UTR-2 as a prognostic parameter indicative for a beneficial course of disease in terms of complete response towards NACT or progression-free survival (PFS). At variance, UTR-4 was an independent risk factor for a reduced OS besides already known parameters. Taken into account the most common HLA-G 3’UTR haplotypes (UTR-1–UTR-7, UTR-18), deduction of the UTR-1/2/4 haplotypes to specific SNPs revealed that the +3003C variant, unique for UTR-4, seemed to favor a detrimental disease outcome, while the +3187G and +3196G variants, unique for UTR-1 or UTR-2, were prognostic parameters for a beneficial course of disease. In conclusion, these data suggest that the HLA-G 3’UTR variants +3003C, +3187G, and +3196G are promising candidates for the prediction of therapy and disease outcome in LABC patients.

Abstract P2-02-04: In early breast cancer, the ratios of neutrophils, monocyctes and platelets to lymphocytes significantly correlate with the presence of subsets of circulating tumor cells in blood and disseminated tumor cells in the bone marrow

Background: Circulating tumor cells (CTCs) are the precursors of metastasis and while travelling through the peripheral blood, they crosstalk with different types of blood cells before they finally reach distant organs to settle down as disseminated tumor cells (DTCs). Proinflammatory markers include the neutrophil lymphocyte ratio (NLR), the platelet lymphocyte ratio (PLR) as well as the monocyte lymphocyte ratio (MLR) and the presence of tumor cells as well as specific proinflammatory markers are two independent predictors of worse outcome in breast cancer (BC). However, little is known about the correlation between NLR, PLR, MLR and subsets of CTCs as well as DTCs in early, non-metastatic BC. Here we evaluated the correlation of NLR, PLR, MLR and the presence of epithelial CTCs (eCTCs), CTCs in epithelial mesenchymal transition (EMT-CTCs) as well as DTCs to better identify patients at risk, to monitor treatment reponse and probably adjust therapeutic options. Methods: The counts of peripheral neutrophils, lymphocytes, monocytes and platelets to determine NLR, PLR and MLR as well as clinicopathological data during diagnosis were retrospectively recorded for 171 patients (pts) diagnosed with BC from July 2006 to December 2012, before the start of therapy. NLR, PLR and MLR were calculated from peripheral blood cell counts and their optimal cutoff levels were determined by the 75% percentile resulting in the following values: NLR: 3.13, MLR: 0.39 and PLR: 222.3, respectively. 170/171 pts were analyzed for DTCs by immunocytochemistry using the pan-cytokeratin antibodyA45-B/B3 (Clodronate intake was recommended in case of DTC-positivity). CTCs were determined in 155/171 pts applying positive immunomagnetic selection using the AdnaTest BreastCancerSelect. The recovered cDNA was tested for the presence of eCTCs and EMT-CTCs using the AdnaTests BreastCancerDetect and EMTDetect. Pts were considered CTC-positive if at least one of the two tests were positive. Statistical analysis included descriptive reporting, U-test for group differences, Rho correlations for dependencies and Fisher's chi-square test for distributional differences. Rho correlations were used to assess the relationship between NLR, PLR, MLR and tumor cells as well as progression-free survival (PFS) and overall survival (OS). Results: DTCs were detected in 34% of the pts and at least one CTC-subtype was found in 28% of the pts. Whereas the presence of DTCs was not associated with PFS or OS, the presence of CTCs significantly correlated with a shorter PFS (p=0.046) and OS (p=0.018). However, neither eCTCs nor EMT-CTSs alone were of prognostic significance. Enhanced lymphocyte (p=0.025) and monocyte counts (p=0.039) as well as a low PLR (p=0.032) significantly correlated with a reduced PFS in pts still alive whereas an enhanced MLR showed a high correlation with a shorter PFS (p=0.007) and OS (p=0.021) in deceased pts. Whereas MLR significantly correlated with the presence of EMT-CTCs (p=0.045), the presence of eCTCs significantly associated with an elevated NLR (p=0.003) and enhanced lymphocyte (p=0.007) as well as monocyte counts (p=0.012). No significant correlations were found for NLR, PLR and MLR with DTCs, however, DTC-positive pts, harboring a lower PLR, had a significant shorter OS (p=0.043). Conclusion: Here we show that proinflammatory markers in blood are closely related to the presence of different CTC subsets in early BC while no direct correlation was found for tumor cell spread to the bone. These findings might improve the prognostication of these pts and probably help to monitor response to therapy and adjust treatment options.

Citation Format: Sabine Kasimir-Bauer, Ebru Karaaslan, Olaf Hars, Ann-Kathrin Bittner, Oliver Hoffmann, Rainer Kimmig. In early breast cancer, the ratios of neutrophils, monocyctes and platelets to lymphocytes significantly correlate with the presence of subsets of circulating tumor cells in blood and disseminated tumor cells in the bone marrow [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-02-04.

Abstract OT2-29-01: neoMono - An adaptive randomized neoadjuvant two arm trial in patients with TNBC comparing a mono atezolizumab window followed by atezolizumab and chemotherapy with atezolizumab and chemotherapy

Background: Improvement of systemic treatment of TNBC represents an unmet medical need. Recently, targeted therapy of regulatory immune pathways has become an important option in the treatment of numerous malignancies including breast cancer. Neoadjuvant trials combining chemotherapy and checkpoint inhibitors (KEYNOTE-522 and IMPASSION031) have demonstrated a meaningful benefit regarding pathological complete remission (pCR) and event-free survival (EFS) for the addition of PD-1- and PD-L1-inhibitors to chemotherapy among patients with TNBC, respectively. In addition, initial analyzes have presented promising results regarding event-free survival. In the neoadjuvant GeparNuevo trial only a subgroup of patients with TNBC, receiving a 2-week checkpoint inhibitor monotherapy window before the start of neoadjuvant chemotherapy in combination with checkpoint inhibition, achieved a pCR benefit as compared to patients treated with neoadjuvant chemotherapy alone. Trial Design: NeoMono is a phase 2 randomized multicenter trial recruiting male and female patients with primary TNBC (defined as ER/PR &lt; 10% and HER2 negative). Neoadjuvant treatment in Arm A and B consists of Atezolizumab 1200 mg every 3 weeks in addition to neoadjuvant chemotherapy (i.e. 12 x Carboplatin and Paclitaxel q1w followed by Epirubicin and Cyclophosphamide q3w) In Arm A this therapy is preceded by Atezolizumab 840 mg q2w (Atezolizumab mono window). Study goals are the comparison of efficacy and safety of neoadjuvant chemotherapy with Atezolizumab with and without Atezolizumab two-week window (primary endpoint: pCR) and the identification of biomarkers predicting (early) response to or resistance against Atezolizumab. The broad translational program of the neoMono trial aims at identifying these biomarkers on tumor and patient level. The neoMono statistical design adapts the idea of a proof-of-concept trial and uses Bayesian posterior and predictive probabilities for inference about the primary hypothesis. Up to four planned efficacy interim analyses provide decision points for early stopping for success or futility. The expected maximum number of patients to be recruited is 458.

Citation Format: Cornelia Kolberg-Liedtke, Johannes Schumacher, Ramona Erber, Michael Braun, Bernhard Heinrich, Oliver Hoffmann, Peter Fasching, Helmut Forstbauer, Anke Kleine-Tebbe, Georg Kunz, Michael Lux, Joachim Rom, Christian Schem, Nicole Stahl, Arndt Hartmann, Sabine Kasimir-Bauer, Hans-Christian Kolberg. neoMono - An adaptive randomized neoadjuvant two arm trial in patients with TNBC comparing a mono atezolizumab window followed by atezolizumab and chemotherapy with atezolizumab and chemotherapy [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-29-01.

Abstract P5-13-33: Longitudinal transcriptional profiling of CTCs in metastatic breast cancer patients receiving the CDK4/6 inhibitor Palbociclib to predict therapy response

Background: CDK4/6 inhibitors represent a new treatment option for metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients. However, predictive markers have not been defined to decide who will benefit from CDK4/6 inhibitors. Circulating tumor cells (CTCs) represent the tumoral heterogeneity in real time and are available for molecular characterization via minimal-invasive sequential blood sampling. Here, we aim to identify biomarkers of resistance to Palbociclib by conducting transcriptional profiling of CTCs before therapy initiation (baseline) and after six months under treatment. Methods: Blood of 50 HR+/HER2-MBC patients drawn at baseline of Palbociclib plus endocrine treatment and blood of 20 HR+/HER2-MBC patients drawn before initiation of endocrine monotherapy, as well as blood samples of these 70 patients after six months under treatment will be analyzed. Patients with progressive disease within the first six months of treatment were defined as non-responders. Isolation of CTCs was conducted using positive immunomagnetic selection targeting EpCAM, EGFR and HER2 (AdnaTest EMT2/StemCell Select). cDNA was analyzed by a new multimarker qPCR panel utilizing QuantiNova LNA Probe assays targeting 25 genes. qPCR data was normalized to CD45 to substract the effect of contaminating leukocytes. Additionally, data was normalized to 20 healthy female donor controls to identify BC specific overexpression signals with a specificity of &gt;90% for all targets. Consumables: QIAGEN, Germany. Results: We successfully established the multimarker qPCR according to the MIQE guidelines. Up to now, the binary mRNA overexpression signals of 25 targets in CTCs isolated at baseline were analyzed in 40 of the total 70 planned MBC patients. In detail, 24 of those 40 patients were treated with Palbociclib plus endocrine therapy, including seven responders and 15 non-resonders, while the 16 other patients were treated with endocrine therapy alone (seven non-responders and nine responders). In the entire cohort, STAT1 signals were significantly related to a decreased overall survival (p=0.0034) and NFKB1 signals correlated significantly with an increased progression free survival (PFS; p=0.027). In the Palbociclib group, CDK2, WWTR1 and YAP1 overexpression signals were more common in non-responders compared with responders. MLH1 and NFKB1 signals were more common in responders than in non-responders. In this cohort, MLH3 overexpression at baseline was significantly correlated with prolonged PFS (p=0.047) and the patient with the longest PFS (35 months) was the only patient with detectable ERBB4, JUN, CETN2 and TEAD2 signals. In the control group treated with endocrine therapy alone, signal prevalence of CXCR4 and STAT1 were increased in the non-responders versus responders and ABCC2, ESR1, FAT4 and FGFR1 signals were more frequently detected in the responders. Conclusion: Transcriptional profiling of CTCs represents a real-time snapshot of the disease complexity. Characterization of the CTCs isolated from blood drawn at baseline is promising for the identification of urgently needed predictive markers (here MLH3 overexpression), while characterization of CTCs isolated under treatment can elucidate the transcriptional dynamics and might be used as monitoring marker by differentiation of non-responders and responders. We will finalize CTC analysis of the entire cohort and will continue blood sampling of additional Palbociclib treated patients, also in the follow-up of the disease, to validate CTC MLH3 overexpression as predictive biomarker for CDK4/6 inhibitor treatment and moreover, to find further overexpression signals in CTCs relevant for MBC therapy management.

Citation Format: Sabine Kasimir-Bauer, Charlotte Gruber, Oliver Hoffmann, Rainer Kimmig, Corinna Keup. Longitudinal transcriptional profiling of CTCs in metastatic breast cancer patients receiving the CDK4/6 inhibitor Palbociclib to predict therapy response [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-13-33.

Single HER2-positive tumor cells are detected in initially HER2-negative breast carcinomas using the DEPArray™-HER2-FISH workflow

Background

In breast cancer (BC), overexpression of HER2 on the primary tumor (PT) is determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to stratify samples as negative, equivocal and positive to identify patients (pts) for anti-HER2 therapy. CAP/ASCO guidelines recommend FISH for analyzing HER2/neu (ERBB2) gene amplification and for resolving equivocal HER2 IHC results. However, pre-analytical and analytical aspects are often confounded by sample related limitations and tumor heterogeneity and HER2 expression may differ between the PT and circulating tumor cells (CTCs), the precursors of metastasis. We used a validation cohort of BC patients to establish a new DEPArray™-PT-HER2-FISH workflow for further application in a development cohort, characterized as PT-HER2-negative but CTC-HER2/neu-positive, to identify patients with PT-HER2 amplified cells not detected by routine pathology.

Methods

50 µm FFPE tumor curls from the validation cohort (n = 49) and the development cohort (n = 25) underwent cutting, deparaffinization and antigen retrieval followed by dissociation into a single-cell suspension. After staining for cytokeratin, vimentin, DAPI and separation via DEPArray™, single cells were processed for HER2-FISH analysis to assess the number of chromosome 17 and HER2 loci signals for comparison, either with available IHC or conventional tissue section FISH. CTC-HER2/neu status was determined using the AdnaTest BreastCancer (QIAGEN, Hilden, Germany).

Results

Applying CAP/ASCO guidelines for HER2 evaluation of single PT cells, the comparison of routine pathology and DEPArray™-HER2-FISH analysis resulted in a concordance rate of 81.6% (40/49 pts) in the validation cohort and 84% (21/25 pts) in the development cohort, respectively. In the latter one, 4/25 patients had single HER2-positive tumor cells with 2/25 BC patients proven to be HER2-positive, despite being HER2-negative in routine pathology. The two other patients showed an equivocal HER2 status in the DEPArray™-HER2-FISH workflow but a negative result in routine pathology. Whereas all four patients with discordant HER2 results had already died, 17/21 patients with concordant HER2 results are still alive.

Conclusions

The DEPArray™ system allows pure tumor cell recovery for subsequent HER2/neu FISH analysis and is highly concordant with conventional pathology. For PT-HER2-negative patients, harboring HER2/neu-positive CTCs, this approach might allow caregivers to more effectively offer anti-HER2 treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-022-01330-8.

Prognostic Significance of SLFN11 Methylation in Plasma Cell-Free DNA in Advanced High-Grade Serous Ovarian Cancer

Background: Epigenetic alterations in ctDNA are highly promising as a source of novel potential liquid biopsy biomarkers and comprise a very promising liquid biopsy approach in ovarian cancer, for early diagnosis, prognosis and response to treatment. Methods: In the present study, we examined the methylation status of six gene promoters (BRCA1, CST6, MGMT, RASSF10, SLFN11 and USP44) in high-grade serous ovarian cancer (HGSOC). We evaluated the prognostic significance of DNA methylation of these six gene promoters in primary tumors (FFPEs) and plasma cfDNA samples from patients with early, advanced and metastatic HGSOC. Results: We report for the first time that the DNA methylation of SLFN11 in plasma cfDNA was significantly correlated with worse PFS (p = 0.045) in advanced stage HGSOC. Conclusions: Our results strongly indicate that SLFN11 epigenetic inactivation could be a predictor of resistance to platinum drugs in ovarian cancer. Our results should be further validated in studies based on a larger cohort of patients, in order to further explore whether the DNA methylation of SLFN11 promoter could serve as a potential prognostic DNA methylation biomarker and a predictor of resistance to platinum-based chemotherapy in ovarian cancer.

Association of Soluble B7-H4 and Circulating Tumor Cells in Blood of Advanced Epithelial Ovarian Cancer Patients

Introduction

Epithelial ovarian cancer (EOC) is the deadliest gynecologic malignancy worldwide. Reliable predictive biomarkers are urgently needed to estimate the risk of relapse and to improve treatment management. Soluble immune-checkpoints in EOC are promising molecules serving as prognostic biomarkers accessible via liquid biopsy. We thus, aimed at elucidating the role of sB7-H4 in EOC.

Material and Methods

We analyzed soluble serum B7-H4 (sB7-H4) using ELISA and circulating tumor cells (CTCs) in blood applying the AdnaTest OvarianCancer in 85 patients suffering from advanced EOC. Findings were correlated with clinical parameters as well as survival data.

Results

sB7-H4 was detectable in 14.1% patients, CTCs in 32.9% patients and simultaneous presence of CTCs and sB7-H4 was found in 7% patients, respectively. Although no association between sB7-H4 and CTC could be documented, each of them served as independent predictive factors for overall survival (OS).

Conclusion

sB7-H4 and CTCs are independent prognostic biomarkers for impaired survival in EOC. As they are easily accessible via liquid biopsy, they may be of potential benefit for the prediction of therapy response and survival for EOC patients.

An Observational Study on Breast Cancer Survival and Lifestyle Related Risk Factors

BACKGROUND/AIM

Breast cancer survivors are increasingly interested in lifestyle modifications in order to reduce the risk of recurrence and mortality. Therefore, we aimed to study the association between survival and lifestyle related risk factors such as obesity, alcohol intake, smoking, medication and atopic diseases.

PATIENTS AND METHODS

In this observational single center study, clinicopathological parameters of 635 women with primary breast cancer were sampled. A logistic regression model was applied to investigate correlations among clinical data and various life style related factors. Patients were stratified according to lifestyle and treatment characteristics. Cox regression and the Kaplan-Meier method were used to analyze survival differences in various patient subsets and to identify possible prognostic factors.

RESULTS

Logistic regression analysis indicated a correlation between low Body Mass Index (BMI) and extended progression-free survival (PFS). Cox regression showed that patients not using beta-blockers had a significantly prolonged overall survival (OS) compared to beta-blocker users [hazard ratio (HR)=3.7; 95% confidence interval (CI)=1.66-8.14, p=0.01]. Apparently, the clincopathological parameters including BMI, HER2-, estrogen receptor (ER) and progesteron receptor (PR)-status as well as treatment with chemo-, radio- and endocrine therapy did not play a role regarding the survival differences between beta-blocker users and non-users.

CONCLUSION

Patients not using beta-blockers appeared to benefit from extended PFS and OS. Further, patients with a rather low BMI (<30 kg/m²) seemed to have a survival benefit compared to obese patients. Particularly, among postmenopausal women, beta-blocker intake and obesity appeared to be possible life style related prognostic factors that could be used for patient stratification.

Integrative statistical analyses of multiple liquid biopsy analytes in metastatic breast cancer

Background

Single liquid biopsy analytes (LBAs) have been utilized for therapy selection in metastatic breast cancer (MBC). We performed integrative statistical analyses to examine the clinical relevance of using multiple LBAs: matched circulating tumor cell (CTC) mRNA, CTC genomic DNA (gDNA), extracellular vesicle (EV) mRNA, and cell-free DNA (cfDNA).

Methods

Blood was drawn from 26 hormone receptor-positive, HER2-negative MBC patients. CTC mRNA and EV mRNA were analyzed using a multi-marker qPCR. Plasma from CTC-depleted blood was utilized for cfDNA isolation. gDNA from CTCs was isolated from mRNA-depleted CTC lysates. CTC gDNA and cfDNA were analyzed by targeted sequencing. Hierarchical clustering was performed within each analyte, and its results were combined into a score termed Evaluation of multiple Liquid biopsy analytes In Metastatic breast cancer patients All from one blood sample (ELIMA.score), which calculates the contribution of each analyte to the overall survival prediction. Singular value decomposition (SVD), mutual information calculation, k-means clustering, and graph-theoretic analysis were conducted to elucidate the dependence between individual analytes.

Results

A combination of two/three/four LBAs increased the prevalence of patients with actionable signals. Aggregating the results of hierarchical clustering of individual LBAs into the ELIMA.score resulted in a highly significant correlation with overall survival, thereby bolstering evidence for the additive value of using multiple LBAs. Computation of mutual information indicated that none of the LBAs is independent of the others, but the ability of a single LBA to describe the others is rather limited—only CTC gDNA could partially describe the other three LBAs. SVD revealed that the strongest singular vectors originate from all four LBAs, but a majority originated from CTC gDNA. After k-means clustering of patients based on parameters of all four LBAs, the graph-theoretic analysis revealed CTC ERBB2 variants only in patients belonging to one particular cluster.

Conclusions

The additional benefits of using all four LBAs were objectively demonstrated in this pilot study, which also indicated a relative dominance of CTC gDNA over the other LBAs. Consequently, a multi-parametric liquid biopsy approach deconvolutes the genomic and transcriptomic complexity and should be considered in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00902-1.

Soluble Neuropilin-1 is an independent marker of poor prognosis in early breast cancer

Background

Neuropilin-1 (NRP-1) is a transmembrane protein that acts as a multifunctional non-tyrosine kinase receptor with an established role in development and immunity. NRP-1 also regulates tumor biology, and high expression levels of tissue NRP-1 have been associated with a poor prognosis. Recently, ELISA-based quantification of soluble NRP-1 (sNRP-1) has become available, but little is known about the prognostic value of sNRP-1 in malignancies.

Materials and methods

We measured sNRP-1 in the serum of 509 patients with primary early breast cancer (BC) at the time of diagnosis using ELISA.

Results

Mean serum values of sNRP-1 were 1.88 ± 0.52 nmol/l (= 130.83 ± 36.24 ng/ml). SNRP-1 levels weakly correlated with age, and were higher in peri- and postmenopausal patients compared to premenopausal patients, respectively (p < 0.0001). Low levels of sNRP-1 were associated with a significant survival benefit compared to high sNRP-1 levels at baseline (p = 0.005; HR 1.94; 95%CI 1.23–3.06). These findings remained significant after adjustment for tumor stage including lymph node involvement, grading, hormone receptor, HER2 status, and age (p = 0.022; HR 1.78; 95%CI 1.09–2.91).

Conclusion

Our findings warrant further investigations into the prognostic and therapeutic potential of sNRP-1 in BC.

Abstract PS2-24: Dynamics of a multi-parametric liquid biopsy, including CTCs, EVs, and cfDNA, during therapy in metastatic breast cancer patients provide useful insights for therapy management

Background: Extensive knowledge about the molecular complexity could benefit therapy management in metastatic breast cancer (MBC). Consequently, we isolated and analyzed mRNA from circulating tumor cells (CTCs), mRNA from extracellular vesicles (EVs), and cell-free DNA (cfDNA) from a minimized blood volume and aimed to assess the dynamics of these analytes to elucidate the relevance of multi-parametric liquid biopsies for therapy monitoring and therapeutic decision-making by studying them at various points in time during the course of the therapy. Methods: 2x 9 ml of EDTA blood was drawn from 35 MBC patients with hormone receptor-positive and HER2 negative primary tumors at the time of disease progression and at two consecutive staging time points. CTCs and their mRNA were isolated using the AdnaTest EMT2/StemCell Select/Detect. Plasma from CTC-depleted blood was used for cfDNA isolation, while mRNA from EVs was isolated using exoRNeasy and the remaining blood. mRNA purified from CTCs and EVs was analyzed by a multimarker qPCR panel targeting 17 transcripts. cfDNA was analyzed with a customized QIAseq Targeted DNA Panel (targeting 17 genes) for Illumina with unique molecular indices. Consumables: QIAGEN, Germany. Results: Data from 35 patients at three time points (105 samples) and 51 parameters [results of 17 genes in three analytes (CTCs, EVs, and cfDNA)] were correlated with therapy outcomes defined by visual staging to examine their value for monitoring. Among the top 15 parameters with the best sensitivity and specificity - regardless of whether or not sensitivity and specificity were jointly examined - most parameters originated from the analysis of CTCs. Among these parameters, a two-tailed Fisher’s exact test revealed ERBB3 CTC signals (96% spec; 22% sens; p=0.022) or a combination of ERBB3 CTC signals or ERBB2 CTC signals (87% spec; 37% sens; p=0.008) to be highly correlated with the time of disease progression. Interestingly, an evaluation of the development of signals during the therapy resulted in EV parameters having the best sensitivity and specificity. The appearance of signals associated with resistance (ERCC1) in EVs was significantly correlated with worse therapy outcomes reaching a specificity of 98% (24% sens; p=0.007). A visualization of all results from seven index patients demonstrated the diversity within CTC signals and the dynamics of EV signals during treatment. Some of the CTC signals and their matched EVs (e.g. BRCA1 signals) showed opposed behavior during the treatment for a given patient. PIK3CA and ESR1 variants, known to be associated with resistance, were frequently found in those index patients receiving anti-hormonal treatment. Allele frequencies of PIK3CA variants in cfDNA and PIK3CA CTC signals showed a similar reduction after successful chemotherapy. In contrast, a switch to chemotherapy induced ERCC1 CTC signals in two cases. In three other cases, ERCC1 CTC signals persisted despite the patients having successfully responded to the chemotherapy administered. In individual patients, only signals from a single analyte were particularly prominent at all time points. Conclusion: Among the parameters tested for the purposes of monitoring, most of the top 15 originated from the analysis of CTCs and therefore, underscore their salience in the field of liquid biopsy. Additionally, the dynamic development of overexpression signals in EVs during the course of therapy proved to be an important indicator of disease progression and might therefore also be useful for therapy monitoring. Combination of these results with the analysis of cfDNA variants over time, as done with our index patients, underlines the usefulness of this multimodal liquid biopsy approach for therapeutic decision-making in the future.

Citation Format: Sabine Kasimir-Bauer, Markus Storbeck, Peter Hahn, Siegfried Hauch, Markus Sprenger-Haussels, Oliver Hoffmann, Rainer Kimmig, Corinna Keup. Dynamics of a multi-parametric liquid biopsy, including CTCs, EVs, and cfDNA, during therapy in metastatic breast cancer patients provide useful insights for therapy management [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS2-24.

Longitudinal Multi-Parametric Liquid Biopsy Approach Identifies Unique Features of Circulating Tumor Cell, Extracellular Vesicle, and Cell-Free DNA Characterization for Disease Monitoring in Metastatic Breast Cancer Patients

Dynamics of mRNA from circulating tumor cells (CTCs), mRNA from extracellular vesicles (EVs), and cell-free DNA (cfDNA) were assessed to examine the relevance of a longitudinal multi-parametric liquid biopsy strategy. Eighteen milliliters of blood was drawn from 27 hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) patients at disease progression and at two subsequent radiologic staging time points. CTC mRNA and EV mRNA were analyzed using multi-marker qPCR, and cfDNA was analyzed using targeted next-generation sequencing (NGS). The presence of ERBB2 or ERBB3 overexpression signals in CTCs significantly correlated with disease progression (87% specificity, 36% sensitivity, p-value = 0.023), and the presence of either ERBB3 signals in CTCs or EVs or cfDNA variants in ERBB3 also showed a significant association with progressive MBC. Fluctuations during treatment were detected in the EV fraction with the appearance of hitherto undetected ERCC1 signals correlating with progressive disease (97% specificity, 18% sensitivity, p-value = 0.030). Allele frequency development of ESR1 and PIK3CA variants detected at subsequent staging time points could be used as a predictor for therapy success and, importantly, might help guide therapy decisions. The three analytes, each with their own unique features for disease monitoring, were shown to be complementary, underlining the usefulness of the longitudinal multi-parametric liquid biopsy approach.

Liquid Biopsies to Evaluate Immunogenicity of Gynecological/Breast Tumors: On the Way to Blood-Based Biomarkers for Immunotherapies

BACKGROUND

Despite the assumption of breast cancer (BC) as a cold, non-immunogenic tumor, immune checkpoint inhibitor (ICI) therapy is favorable for a subgroup of patients. Immunohistochemical assessment of the programmed cell death ligand 1 (PD-L1) is the only approved companion diagnostic for anti-PD-L1 therapy in metastatic triple-negative BC; however, challenges regarding the standardization of PD-L1 scoring in tumor tissue still remain. Consequently, to select patients most likely to respond to ICI, blood-based biomarkers are urgently needed.

SUMMARY AND KEY MESSAGES

Liquid biopsy, comprising circulating immune cells, circulating tumor cells and extracellular vesicles, as well as their surface proteins, is of high potential, and these analytes were already shown to be molecular correlates or regulators of the evasion from antitumoral immune reaction. Liquid biopsy, also enabling the evaluation of tumor mutational burden (TMB), microsatellite instability, and the T-cell receptor repertoire, allows serial sampling for monitoring purposes and reflects intra-tumoral heterogeneity which qualifies as marker for immunogenicity. Only a very few studies have already elucidated the potential of these analytes as biomarkers under ICI therapy. Nonetheless, the topic is of growing interest and has high relevance for the future. However, for clinical implementation, these multifarious analytes first need to pass robust standardization and validation procedures.

A proposal for score assignment to characterize biological processes from mass spectral analysis of serum

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Biological process-associated scores generated from mass spectrometry of serum.

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Scores demonstrated acceptable levels of reproducibility.

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Scores associated with biological processes and clinical outcome in cancer patients.

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Possible application to biomarker studies for treatment or monitoring of disease.

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Multiple biological processes assessed from 3 µL of serum.

Introduction

Most diseases involve a complex interplay between multiple biological processes at the cellular, tissue, organ, and systemic levels. Clinical tests and biomarkers based on the measurement of a single or few analytes may not be able to capture the complexity of a patient’s disease. Novel approaches for comprehensively assessing biological processes from easily obtained samples could help in the monitoring, treatment, and understanding of many conditions.

Objectives

We propose a method of creating scores associated with specific biological processes from mass spectral analysis of serum samples.

Methods

A score for a process of interest is created by: (i) identifying mass spectral features associated with the process using set enrichment analysis methods, and (ii) combining these features into a score using a principal component analysis-based approach. We investigate the creation of scores using cohorts of patients with non-small cell lung cancer, melanoma, and ovarian cancer. Since the circulating proteome is amenable to the study of immune responses, which play a critical role in cancer development and progression, we focus on functions related to the host response to disease.

Results

We demonstrate the feasibility of generating scores, their reproducibility, and their associations with clinical outcomes. Once the scores are constructed, only 3 µL of serum is required for the assessment of multiple biological functions from the circulating proteome.

Conclusion

These mass spectrometry-based scores could be useful for future multivariate biomarker or test development studies for informing treatment, disease monitoring and improving understanding of the roles of various biological functions in multiple disease settings.

Circulating Tumor Cells Expressing the Prostate Specific Membrane Antigen (PSMA) Indicate Worse Outcome in Primary, Non-Metastatic Triple-Negative Breast Cancer

Background: We analyzed mRNA profiles of prostate cancer related genes in circulating tumor cells (CTCs) of primary, non-metastatic triple-negative breast cancer (TNBC) patients (pts) before and after neoadjuvant chemotherapy to elucidate the potential of prostate cancer targets in this BC subgroup.

Method: Blood from 41 TNBC pts (n = 41 before / 26 after therapy) was analyzed for CTCs applying the AdnaTest EMT-2/Stem Cell Select. Multimarker RT-qPCR allowed the detection of the prostate specific antigen PSA, the prostate specific membrane antigen PSMA, full-length androgen receptor (AR-FL), and AR splice-variant seven (AR-V7).

Results: Before therapy, at least one prostate cancer related gene was detected in 15/41 pts (37%). Notably, in 73% of AR-FL positive cases, AR-V7 was co-expressed. After therapy, CTCs of only one patient harbored prostate cancer related genes. AR-V7+ and PSMA+ CTCs significantly correlated with early relapse (p = 0.041; p = 0.00039) whereas PSMA+ CTCs also associated with a reduced OS (p = 0.0059). This correlation was confirmed for PSMA+ CTCs in univariate (PFS p = 0.002; OS p = 0.015), but not multivariate analysis.

Conclusion: Although CTCs that expressed prostate cancer related genes were eliminated by the given therapy, PSMA+ CTCs significantly identified pts at high risk for relapse. Furthermore, AR inhibition, often discussed for this BC subgroup, might not be successful in the primary setting of the disease since we identified AR-FL+ CTCs together with AR-V7+ CTCs, associated with therapeutic failure.

Abstract 5366: Metastatic breast cancer subgroup specific mRNA profiles of circulating tumor cells and extracellular vesicles

Background: We recently demonstrated great differences in the RNA profiles of matched circulating tumor cells (CTCs) and extracellular vesicles (EVs) in HER2 negative (HER2-) hormone receptor positive (HR+) metastatic breast cancer (MBC) patients. To elucidate the clinical utility of CTC and EV RNA profiling, we here a) tested the RNA profiles of another MBC subgroup, namely the HER2 positive (HER2+) patients, and b) compared the profiles in the two cohorts.

Patients and methods: Blood was collected from 25 HER2+ (HR+ and HR-) and 35 HER2- (only HR+) MBC patients at the time of disease progression and at two consecutive staging time points. CTCs were isolated from 5 ml blood by positive immunomagnetic selection targeting EpCAM, EGFR and HER2 (AdnaTest EMT2/StemCell Select). EVs were isolated from 4 ml pre-filtered plasma by affinity-based binding to a spin column (exoRNeasy). The mRNA was purified by Oligo-dT beads and reverse transcribed (AdnaTest EMT2/StemCell Detect). Pre-amplified cDNA was analyzed by multimarker qPCR assays (AdnaTest TNBC Panel prototype) for 18 genes (including AKT2, ALK, AR, AURKA, BRCA1, KIT, MET, EGFR, ERCC1, ERBB2, ERBB3, KRT5, mTOR, NOTCH1, PARP1, PIK3CA, SRC, GAPDH). Consumables: QIAGEN, Germany.

Results: In the HER2+ cohort, transcripts involved in the PI3K pathway were significantly more prevalent in CTCs compared to EVs and were found in more than 50% of these patients. In contrast, NOTCH1 and PARP1 were significantly more prominent in EVs as compared to their matched CTCs and EV PARP1 and EV AURKA overexpression signals were detected in more than 50% of patients. ERCC1 and SRC signals were present in CTCs as well as EVs in the majority of patients. ERCC1 signals in CTCs and EVs showed a significantly higher frequency in the HER2+ compared to the HER2-HR+ cohort. However, ERCC1 signals in CTCs of the HER2-HR+ cohort correlated with shorter survival time after first diagnosis of metastasis (p=0.011). In general, the overexpression signal prevalence was similar in both cohorts and both blood analytes. A small overlap of identical signals in CTCs and EVs of 15%/5% in the HER2+/HER2-HR+ cohort was observed. Interestingly, ERBB2 signals were only found in CTCs, not EVs, and in both cohorts with a similar prevalence (36%/40%). ERBB3 overexpression signals in CTCs significantly correlated with non-response only in the HER2-HR+ cohort (p=0.021). However, in HER2+ patients ERBB3 signals were only present at the time of progressive disease, but not at the time point of stable disease.

Conclusions: RNA profiling indicated great differences in CTCs and EVs in both subgroups. Moreover, data emphasize the immense diversity between HER2+ versus HER2-HR+ MBC patients, revealing the need for blood analyte specific and subgroup specific multimarker panel for therapy management based on liquid biopsies in the future.

Citation Format: Corinna Keup, Siegfried Hauch, Mitra Tewes, Hans-Christian Kolberg, Oliver Hoffmann, Rainer Kimmig, Sabine Kasimir-Bauer. Metastatic breast cancer subgroup specific mRNA profiles of circulating tumor cells and extracellular vesicles [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5366.

6-Color/1-Target Immuno-SERS Microscopy on the Same Single Cancer Cell

There is an urgent clinical need for multicolor imaging of single cancer cells (no ensemble averaging) for identifying heterogenous expression of predictive biomarkers. Specifically, the comprehensive characterization of single disseminated tumor cells (sDTCs) responsible for metastatic relapse is the key to personalized therapy for patients. Current bioimaging methods lack the necessary multicolor capacity and suffer from background/autofluorescence. Both these central limitations can be overcome by immuno-SERS microscopy using SERS nanotags conjugated to antibodies. Here, we demonstrate the proof of concept for 6-color iSERS microscopy on the same single cancer cell. Human epidermal growth factor receptor 2 (HER2), the most prominent breast cancer marker, is localized on the membrane of single SkBr-3 cells, which overexpress HER2 and are an accepted model for sDTCs in breast cancer. This work paves the way for future multicolor/multitarget imaging for characterizing heterogeneous protein expression at the single-cell level.

Molecular characterization of circulating tumour cells identifies predictive markers for outcome in primary, triple-negative breast cancer patients

mRNA profiles of circulating tumour cells (CTCs) were analysed in patients with triple‐negative breast cancer (TNBC) (pts) before (BT) and after therapy (AT) to identify additional treatment options. 2 × 5 mL blood of 51 TNBC pts and 24 non‐TNBC pts (HR+/HER2−; HR−/HER2+) was analysed for CTCs using the AdnaTest EMT‐2/Stem Cell Select™, followed by mRNA isolation and cDNA analysis for 17 genes by qPCR PIK3CA, AKT2, MTOR and the resistance marker AURKA and ERCC1 were predominantly expressed in all breast cancer subtypes, the latter ones especially AT. In TNBC pts, ERBB3, EGFR, SRC, NOTCH, ALK and AR were uniquely present and ERBB2+/ERBB3 + CTCs were found BT and AT in about 20% of cases. EGFR+/ERBB2+/ERBB3 + CTCs BT and ERBB2+/ERBB3 + CTCs AT significantly correlated with a shorter progression‐free survival (PFS; P = 0.01 and P = 0.02). Platinum‐based therapy resulted in a reduced PFS (P = 0.02) and an induction of PIK3CA expression in CTCs AT. In non‐TNBC pts, BT, the expression pattern in CTCs was similar. AURKA+/ERCC1 + CTCs were found in 40% of HR−/HER2 + pts BT and AT. In the latter group, NOTCH, PARP1 and SRC1 were only present AT and ERBB2 + CTCs completely disappeared AT. These findings might help to predict personalized therapy for TNBC pts in the future.

CXCR4 and JUNB double-positive disseminated tumor cells are detected frequently in breast cancer patients at primary diagnosis

Background:

The chemokine receptor CXCR4 and the transcription factor JUNB, expressed on a variety of tumor cells, seem to play an important role in the metastatic process. Since disseminated tumor cells (DTCs) in the bone marrow (BM) have been associated with worse outcomes, we evaluated the expression of CXCR4 and JUNB in DTCs of primary, nonmetastatic breast cancer (BC) patients before the onset of any systemic treatment.

Methods:

Bilateral BM (10 ml) aspirations of 39 hormone receptor (HR)-positive, HER2-negative BC patients were assessed for the presence of DTCs using the following combination of antibodies: pan-cytokeratin (A45-B/B3)/CXCR4/JUNB. An expression pattern of the examined proteins was created using confocal laser scanning microscopy, Image J software and BC cell lines.

Results:

CXCR4 was overexpressed in cancer cells and DTCs, with the following hierarchy of expression: SKBR3 > MCF7 > DTCs > MDA-MB231. Accordingly, the expression pattern of JUNB was: DTCs > MDA-MB231 > SKBR3 > MCF7. The mean intensity of CXCR4 (6411 ± 334) and JUNB (27725.64 ± 470) in DTCs was statistically higher compared with BM hematopoietic cells (2009 ± 456, p = 0.001; and 11112.89 ± 545, p = 0.001, respectively). The (CXCR4+JUNB+CK+) phenotype was the most frequently detected [90% (35/39)], followed by the (CXCR4–JUNB+CK+) phenotype [36% (14/39)]. However, (CXCR4+JUNB–CK+) tumor cells were found in only 5% (3/39) of patients. Those patients harboring DTCs with the (CXCR4+JUNB+CK+) phenotype revealed lower overall survival (Cox regression: p = 0.023).

Conclusions:

(CXCR4+JUNB+CK+)-expressing DTCs, detected frequently in the BM of BC patients, seem to identify a subgroup of patients at higher risk for relapse that may be considered for close follow up.

Abstract P5-01-14: The combined blood analysis of cell-free DNA and genomic DNA of circulating tumor cells reveals additive value in hormone receptor-positive, HER2-negative metastatic breast cancer patients

Background: To gain comprehensive insights into the genomic complexity useful for therapy management in metastatic breast cancer (MBC), we aimed to isolate and analyze genomic DNA (gDNA) from circulating tumor cells (CTCs) and matched cell-free DNA (cfDNA) from a minimized blood volume. Methods: EDTA blood was drawn from 27 MBC patients with hormone receptor-positive and HER2 negative primary tumors at the time of disease progression. CTCs and CTC mRNA were isolated from 2 × 5 ml whole blood using the AdnaTest EMT2/StemCell Select/Detect. Plasma of CTC-depleted blood was used for cfDNA isolation. gDNA from CTCs was isolated from the mRNA-depleted CTC lysates using the AllPrep DNA/RNA Nano Kit prototype. CTC gDNA and cfDNA were analyzed with a customized QIAseq Targeted DNA Panel for Illumina with unique molecular indices (UMIs) analyzing AKT1, AR, BRCA1, BRCA2, EGFR, ERCC4, ERBB2, ERBB3, ESR1, FGFR1, KRAS, MUC16, PIK3CA, PIK3R1, PTEN, PTGFR and TGFB1. The library preparation protocol was slightly modified for the usage of CTC gDNA using the entire amount of the CTC gDNA eluate as input without pre-quantification followed by fragmentation and ligation with an increased number of adapters. All libraries were analyzed by paired-end sequencing on the Illumina NextSeq Sequencer with a NextSeq 550 System High-Output Kit, 2 × 150 bp reads with a mean coverage of 11000 x (CTC gDNA) and 8000 x (cfDNA). Consumables: QIAGEN, Germany. Results: Isolation of CTC gDNA and cfDNA was successfully established in a condensed workflow. The UMI coverage observed for cfDNA (2000 x) differed from the UMI coverage for CTC gDNA (500 x), resulting in dramatically increased lowest detectable allele frequency (AF) called with a confidence of 90% in CTC gDNA compared to cfDNA. On average, 6 CTC gDNA variants and 2 cfDNA variants were detected in each patient. Most variants were found in the MUC16 gene in both analytes. BRCA2 variants were the second most prevalent variants in CTC gDNA and cfDNA. PIK3CA and ESR1 variants were less common in CTC gDNA compared with cfDNA, while ERBB2 variants were only detected in CTC gDNA. 57% of all cfDNA variants (29/51) were recovered in the matched CTC gDNA, while 89% of all variants were unique in either CTC gDNA (125 variants) or cfDNA (22 variants). On average, the cfDNA variants with low AF (mean 15%) were not detected in CTC gDNA, while the cfDNA variants that were also found in CTC gDNA exhibited a mean AF of 44%. Similarly, the unique CTC gDNA variants had a mean AF of 23%, while the shared variants were prevalent with a mean AF of 47% in the CTC gDNA fraction. Comparing the patients, 11%/14% of the single CTC gDNA / cfDNA variants were detected in more than one patient, hence the majority of variants was patient-specific. The portion of patients without detectable cfDNA variants or CTC gDNA variants was 15% (4/27) / 11% (3/27), but combined analysis of CTC gDNA and cfDNA identified variants in 26 of all 27 MBC patients (96%). Conclusion: cfDNA and CTC gDNA showed additive variant information. Thus, it is advised to assess cfDNA and CTC gDNA variants to receive a comprehensive genomic picture that might enable to identify the most suitable therapy regimen in each individual patient in the future.

Citation Format: Corinna Keup, Ann-Kathrin Bittner, Oliver Hoffmann, Mitra Tewes, Markus Storbeck, Peter Hahn, Siegfried Hauch, Markus Sprenger-Haussels, Rainer Kimmig, Sabine Kasimir-Bauer. The combined blood analysis of cell-free DNA and genomic DNA of circulating tumor cells reveals additive value in hormone receptor-positive, HER2-negative metastatic breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-01-14.

Abstract P4-01-11: Circulating tumor cells expressing the prostate specific membrane antigen PSMA indicate worse outcome in triple-negative breast cancer patients at primary diagnosis

Background: Triple negative breast cancer (TNBC) is known for its aggressive behavior and poor prognosis since treatment options are limited. Specific biomarkers are urgently needed to treat patients (pts) accordingly. In this regard, circulating tumor cells (CTCs) are discussed to be an ideal surrogate marker for individualized treatment options. We here comprehensively analyzed mRNA profiles of CTCs from TNBC pts before and after neoadjuvant chemotherapy including the expression of prostate related genes [androgen receptor (AR), its splice variant ARV7, the prostate specific antigen (PSA) and the prostate specific membrane antigen (PSMA)] to further elucidate these markers as targets for personalized treatment. Methods: 2 × 5 ml blood of 34 TNBC pts before and 22 pts after therapy were analyzed for CTCs applying positive immunomagnetic selection using the AdnaTest EMT-2/Stem Cell Select (QIAGEN, Germany). Subsequently, cDNA was pre-amplified for specific genes using TaqMan PreAmp Master Mix according to in house designed assays. A 19 gene qPCR panel was performed including AKT2, ALK, AR, AURKA, BRCA1, EGFR, ERCC1, ERBB2, ERBB3, KIT, KRT5, MET, MTOR, NOTCH1, PARP1, PIK3CA, SRC, CD45 (leucocyte control) and GAPDH (housekeeping gene) as well as an internal reference. The cutoff was calculated, taking the false positive rate in healthy donors into account, and defined as Ct (cutoff) - Ct (sample) - [Ct (CD45cutoff) - Ct (CD45sample)]. Using the AdnaPanel Prostate Cancer (QIAGEN, Germany), cDNA was further analyzed for the expression profile of AR, ARV7, PSA and PSMA, respectively. Results: Before therapy, at least one of the prostate related genes was detected in 50% of the pts, resulting in the expression of AR in 35%, ARV7 in 24%, PSMA in 18%, and PSA in 15% of cases, respectively. Notably, in 75% of AR-positive cases, ARV7 was also expressed on CTCs. After therapy, prostate related genes were only detected in two pts, expressing AR, ARV7 and PSA (n=1) and AR (n=1), respectively. Before therapy, the presence of PSMA-positive CTCs alone (p=0.026) or in combination with ARwildtype/ARV7-positive CTCs (p=0.014) significantly correlated with early relapse. Interestingly, this expression pattern was highly related to the expression of genes belonging to the ERBB family (EGFR, ERBB2, ERBB3; p=0.034). Either ERRB family or PSMA expression on CTCs in TNBC was detected in about 70% of the cases analyzed with 90% relapses predicted. Conclusion: Although AR and its splice variant were detected on CTCs in one third of the pts before therapy, these markers do not seem to be relevant with regard to be considered as targets for additional treatment options. In contrast, although expressed in a minority of pts, PSMA-positive CTCs at primary diagnosis indicated worse outcome and should be included in CTC-multimarker panel analysis to identify pts at higher risk for relapse. This study is ongoing and the analysis of more pts will finally show whether these results can be confirmed.

Citation Format: Sabine Kasimir-Bauer, Corinna Keup, Oliver Hoffmann, Siegfried Hauch, Rainer Kimmig, Ann-Kathrin Bittner. Circulating tumor cells expressing the prostate specific membrane antigen PSMA indicate worse outcome in triple-negative breast cancer patients at primary diagnosis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-01-11.

High serum levels of periostin are associated with a poor survival in breast cancer

PURPOSE

Periostin is a secreted extracellular matrix protein, which was originally described in osteoblasts. It supports osteoblastic differentiation and bone formation and has been implicated in the pathogenesis of several human malignancies, including breast cancer. However, little is known about the prognostic value of serum periostin levels in breast cancer.

METHODS

In this study, we analyzed serum levels of periostin in a cohort of 509 primary, non-metastatic breast cancer patients. Disseminated tumor cell (DTC) status was determined using bone marrow aspirates obtained from the anterior iliac crests. Periostin levels were stratified according to several clinical parameters and Pearson correlation analyses were performed. Kaplan-Meier survival curves were assessed by using the log-rank (Mantel-Cox) test. To identify prognostic factors, multivariate Cox regression analyses were used.

RESULTS

Mean serum levels of periostin were 505 ± 179 pmol/l. In older patients (> 60 years), periostin serum levels were significantly increased compared to younger patients (540 ± 184 pmol/l vs. 469 ± 167 pmol/l; p < 0.0001) and age was positively correlated with periostin expression (p < 0.0001). When stratifying the cohort according to periostin serum concentrations, the overall and breast cancer-specific mortality were significantly higher in those patients with high serum periostin (above median) compared to those with low periostin during a mean follow-up of 8.5 years (17.7% vs. 11.4% breast cancer-specific death; p = 0.03; hazard ratio 1.65). Periostin was confirmed to be an independent prognostic marker for breast cancer-specific survival (p = 0.017; hazard ratio 1.79). No significant differences in serum periostin were observed when stratifying the patients according to their DTC status.

CONCLUSIONS

Our findings emphasize the relevance of periostin in breast cancer and reveal serum periostin as a potential marker for disease prediction, independent on the presence of micrometastases.

Digital Immune-Related Gene Expression Signatures In High-Grade Serous Ovarian Carcinoma: Developing Prediction Models For Platinum Response

Purpose

Response to platinum-based therapy is a major prognostic factor in high-grade serous ovarian cancer (HGSOC). While the exact mechanisms of platinum-resistance remain unclear, evidence is accumulating for a connection between the organism’s immune-response and response to platinum. However, predictive tools are missing. This study was performed to examine the putative role of the genetic tumor immune-microenvironment in mediating differential chemotherapy response in HGSOC patients.

Patients and methods

Expression profiling of 770 immune-related genes was performed in tumor tissues from 23 HGSOC cases. Tumors were screened for prognostic and predictive biomarkers using the NanoString nCounter platform for digital gene expression analysis with the appurtenant PanCancer Immune Profiling panel. As validation cohort, gene expression data (RNA Seq) of 303 patients with epithelial ovarian carcinoma (EOC) were retrieved from the The Cancer Genome Atlas (TCGA) database. Different scoring-systems were computed for prediction of risk-of-resistance to cisplatin, disease-free survival (DFS) and overall survival (OS).

Results

Validated on the TCGA-dataset, the developed scores identified 11 significantly differentially expressed genes (p <0.01**) associated with platinum response. HSD11B1 was highly significantly associated with lower risk of recurrence and 7 targets were found highly significantly influencing OS time (p <0.01**).

Conclusion

Our results suggest that response to platinum-based therapy and DFS in ovarian HGSOC is associated with distinct gene-expression patterns related to the tumor immune-system. We generated predictive scoring systems which proved valid when applied to a set of 303 EOC patients.

Soluble Programmed Death Receptor Ligands sPD-L1 and sPD-L2 as Liquid Biopsy Markers for Prognosis and Platinum Response in Epithelial Ovarian Cancer

Introduction: Response to platinum-based therapy is a major prognostic factor in epithelial ovarian cancer (EOC) and reliable prognostic biomarkers are urgently needed to identify patients at high risk. Since ligands of the Programmed Death Receptor-1 (PD-L1 and PD-L2) play a crucial role within the tumor microenvironment for tumorigenesis, we investigated levels of sPD-L1 and sPD-L2 in liquid biopsies of serum samples, and correlated the results with the clinical status, presence of circulating tumor cells (CTCs) and disease outcome in primary EOC patients.

Methods: sPD-L1 and sPD-L2 were determined by ELISA in patients (N = 83) and healthy females (N = 29). Gene expression analysis of EpCAM, MUC-1, CA-125, and ERCC1 was performed by RT-PCR after CTCs enrichment.

Results: sPD-L1 was significantly (p = 0.0001) increased and sPD-L2 decreased (p = 0.003) in EOC patients compared to controls. While enhanced sPD-L1 was associated with residual tumor burden (p = 0.022), reduced sPD-L2 levels were related to platinum-resistance (p < 0.01) and the presence of ERCC1+ CTCs (p < 0.0001). High sPD-L1 levels were associated with a reduced 5 year overall survival (OS, p = 0.003) and progression-free survival (PFS, p = 0.019). Strikingly, sPD-L1 levels >6.4 pg/ml were indicative of a reduced OS (p = 0.035) and PFS (p = 0.083) in platinum-sensitive patients, while OS and PFS in platinum-resistant patients did not differ when patients were stratified to this cut-off.

Conclusions: Our study highlights sPD-L1 and sPD-L2 as complementary biomarkers reflecting clinical status, treatment response and disease outcome of EOC patients. Especially, sPD-L1 may facilitate the identification of high-risk patients with unfavorable disease outcomes despite platinum-sensitivity arguing for additional therapeutic approaches. As sPD-L1 and sPD-L2 are easily accessible via liquid biopsy, the inclusion of sPD-L1 and sPD-L2 in addition to CTC investigation as markers for risk assessment during patient therapy planning and follow-up appears to be a valuable approach.

Prognostic significance of PD-1 and PD-L1 positive tumor-infiltrating immune cells in ovarian carcinoma

INTRODUCTION

Ovarian carcinoma is associated with the highest mortality of all gynecologic malignancies. Even after optimal treatment, prognosis remains poor. There is no established biomarker to predict individual patient outcome.

OBJECTIVE

To evaluate the prognostic significance of PD-1 and PD-L1 expression in tumor tissues from patients with ovarian cancer.

METHODS

Tissue micro-arrays were prepared from routinely formalin-fixed, paraffin-embedded tumor tissues and examined immunohistochemically for the expression of programed cell death protein 1 (PD-1) and one of its ligands (PD-L1) on epithelial tumor cells, as well as on tumor- and stroma-infiltrating immune cells.

RESULTS

The presence of PD-1 positive tumor-infiltrating immune cells was significantly associated with prolonged overall survival. PD-1 and PD-L1 positive tumor-infiltrating immune cells were associated with the presence of lymph node metastases and higher tumor grade. Interestingly, the amount of PD-1/PD-L1 positive tumor- and stroma-infiltrating immune cells independent of PD-1 or PD-L1 expression did not show any significant correlation with prognostic variables.

CONCLUSION

Our results highlight the prognostic value of PD-1 and PD-L1 positive tumor-infiltrating immune cells in ovarian carcinoma. Their association with favorable prognosis supports the hypothesis that the expression of PD-1 and PD-L1 on tumor-infiltrating immune cells represents a strong immune response.

Abstract 2277: Workflow evaluation for molecular characterization of single circulating tumor cells in blood samples of patients with gynecological malignancies

Background: We recently presented the feasibility of single circulating tumor cell (CTC) analysis using the QIAscout single cell isolation platform (QIAGEN), followed by whole transcriptome amplification (WTA) and targeted Next Generation Sequencing (NGS). We here applied this workflow in blood samples of patients (pts) with metastatic breast cancer (MBC) and primary ovarian cancer (POC) and compared the result with a new workflow for single cell transcriptome analysis applying the QIAseq UPX 3' Transcriptome Kit (QIAGEN) for high throughput gene expression analysis.

Methods: 5 ml blood of 7 MBC and 3 POC pts were analyzed for CTCs using the AdnaTest EMT2/StemCell SelectTM, followed single cell isolation. Adhesion of CTCs to the QIAscout array microrafts was supported by pre-treating the array with Corning® Cell-TakTM Adhesive. Single CTCs have been identified utilizing an inverted microscope, and isolated with the QIAscout single cell isolation platform. Subsequently, mRNA of single cells was amplified by WTA (REPLI-g WTA Single Cell Kit, QIAGEN) and cDNA of the cells was further analyzed by targeted NGS using a QIAseq™ Targeted RNA Panel (Human Cancer Transcriptome Panel, 395 genes). Applying the QIAseq UPX 3' Transcriptome Kit, each single cell was tagged with an individual cell ID-sequence and each RNA molecule was simultaneously tagged with an unique molecular index (UMI) during reverse transcription. Tagging of each individual cDNA molecule enabled pooling of all samples for subsequent amplification and library preparation steps, followed by high-throughput NGS. Methods were validated in spike-in experiments using different cell lines spiked into blood of healthy donors.

Results: Using the QIAscout in combination with the WTA-workflow, we have already demonstrated an absent leukocyte contamination. However, only a very few of the detected cells in MBC pts (15%) were finally applicable for NGS. Nevertheless, analyzable CTCs expressed genes involved in angiogenesis (ITGB3), cell cycle (CCND2) and apoptosis (FASLG & SKP2). Applying the UPX 3' Transcriptome-workflow, the number of analyzable CTCs could be markedly improved as documented in spike-in experiments as well as in blood samples of MBC and POC pts. Up to now, in the latter group, we were able to isolate a total number of 84 CTCs [median 25 CTCs (range 24-35 cells)] with 44/84 (52%) ID-sequences detected, being applicable for NGS. Experiments and detailed transcriptome profiling of CTCs are ongoing to be presented at the meeting.

Conclusion: Although both described workflows have to be further evaluated in more detail, the QIAscout single cell isolation platform allows subsequent transcriptome analysis followed by NGS to get insights into single cell heterogeneity for further therapeutic strategies.

Citation Format: Janina Levermann, Norbert Hochstein, Paul Buderath, Benjamin Franken, Siegfried Hauch, Charline Bemmann, Rainer Kimmig, Sabine Kasimir-Bauer. Workflow evaluation for molecular characterization of single circulating tumor cells in blood samples of patients with gynecological malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2277.

Abstract 1369: Establishment of a workflow for analysis of mRNA and gDNA from circulating tumor cells, extracellular vesicles and cell-free DNA from the same blood sample to mirror the genomic and transcriptomic complexity in metastatic breast cancer patients

Background: Blood analytes derived from liquid biopsies are discussed as useful tools for therapy stratification and for monitoring of clonal evolution. To gain comprehensive insights into the genomic and transcriptomic complexity in metastatic breast cancer (MBC) useful for therapy management, we aimed to isolate and analyze mRNA and gDNA from circulating tumor cells (CTCs), mRNA from extracellular vesicles (EVs) and cell-free DNA (cfDNA) from the same blood sample with minimized volume in a condensed workflow.

Patients and Methods: EDTA blood (2x 9 ml) was drawn from 35 MBC patients with hormone receptor positive and HER2 negative primary tumor at time of disease progression and at two further consecutive staging time points. CTCs were isolated in duplicate from 5ml blood by immunomagnetic selection (AdnaTest EMT2/StemCell Select, QIAGEN). Plasma (4 ml) of the CTC-depleted blood was used for cfDNA isolation (QIAamp MinElute ccfDNA Kit, QIAGEN), plasma (4 ml) from the blood not used for CTC/cfDNA isolation was applied for EV isolation (exoRNeasy, QIAGEN). The mRNA purified from CTCs and EVs was analyzed by qPCR panel (AdnaPanel TNBC prototype, QIAGEN), while cfDNA was analyzed with a customized QIAseq Targeted DNA Panel for Illumina (QIAGEN) with unique molecular indices. We are working on a workflow to isolate gDNA from CTCs, starting from mRNA-depleted CTC lysates and analyzing the gDNA with a customized QIAseq Targeted DNA Panel. Isolation and mutation analysis of CTC gDNA was shown to be feasible in spiking experiments.

Results: Isolation of mRNA and gDNA from CTCs, mRNA from EVs and cfDNA was successfully established in a parallel workflow. CTC and EV mRNA profiles showed substantial differences synergizing with regard to their clinical relevance. Whereas overexpression of mTOR was related to therapy responsiveness in CTCs, mTOR signals in EVs related to therapy failure. ERBB2 overexpressing CTCs were found in one third of all MBC patients enabling new therapeutic options. Matched cfDNA revealed the appearance of pathogenic mutations (e.g. PIK3CA H1047R) across treatment indicating underlying resistance mechanisms. Moreover, we identified significant correlations of therapy outcome with the overexpression of transcripts/ presence of mutations in each of the isolated liquid biopsy analytes. Comparison of CTC gDNA and cfDNA is further conducted.

Conclusions: We were able to describe a complete workflow for parallel CTC mRNA, CTC gDNA, EV mRNA and cfDNA isolation from a minimized blood volume. In this research study each analyte showed synergistic potential for therapy management, thus the comprehensive picture of the genomic and transcriptomic complexity might in future enable to identify the most suitable therapy regiment in each individual patient.

Citation Format: Corinna Keup, Markus Storbeck, Peter Hahn, Siegfried Hauch, Markus Sprenger-Haussels, Ann-Kathrin Bittner, Oliver Hoffmann, Mitra Tewes, Rainer Kimmig, Sabine Kasimir-Bauer. Establishment of a workflow for analysis of mRNA and gDNA from circulating tumor cells, extracellular vesicles and cell-free DNA from the same blood sample to mirror the genomic and transcriptomic complexity in metastatic breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1369.

Targeted deep sequencing revealed variants in cell-free DNA of hormone receptor-positive metastatic breast cancer patients

Cell-free DNA (cfDNA) is described to mirror intratumoral heterogeneity and gives insight about clonal evolution for improved therapeutic decisions. We sequenced cfDNA of a hormone receptor-positive, HER2-negative metastatic breast cancer (MBC) cohort with a high coverage to examine the prevalence and relevance of any detected variant. cfDNA of 44 MBC patients was isolated, followed by library construction using a customized targeted DNA panel with integrated unique molecular indices analyzing AKT1, AR, BRCA1, BRCA2, EGFR, ERCC4, ERBB2, ERBB3, ESR1, FGFR1, KRAS, MUC16, PIK3CA, PIK3R1, PTEN, PTGFR, and TGFB1. CfDNA was sequenced on the NextSeq^® 550 platform (Illumina) and variants were analyzed with Ingenuity Variant Analysis (QIAGEN). We evaluated cfDNA variants in 40 of the 44 hormone receptor-positive and HER2-negative patients with a high mean coverage of 22,000×, resulting in MUC16, BRCA2, ERBB3, and AR variant calling in > 90% of the patients. 47% of all AR variants were pathogenic and at least one pathogenic or likely pathogenic variant was detected in each patient. A specific BRCA1 variant and > 3.5 pathogenic variants significantly associated with a reduced survival after diagnosis of metastasis. Longitudinal monitoring revealed an increase of pathogenic and likely pathogenic PIK3CA and ESR1 variant allele frequency under everolimus and exemestane, 8 months before proof of therapy failure by visual staging in one exemplary case. The identification of new variants with high prevalence, prognostic value, and dynamics under treatment by deep sequencing of cfDNA might empower sensitive monitoring and personalized therapeutic decisions.

Fast and reproducible iSERS microscopy of single HER2-positive breast cancer cells using gold nanostars as SERS nanotags

Speed is often a bottleneck in conventional Raman microscopy on biological specimens. In immuno-Raman microspectroscopy, or for short iSERS microscopy, the acquisition times per pixel have been reduced by more than one order of magnitude over the past decade since its proof of concept. Typically rather high laser power densities are employed with the intention of compensating for the shorter acquisition times, without checking the reproducibility of the results in repeated experiments on the same sample. Here, we systematically analyze this aspect at the single-cell level since it forms the basis of quantification and is very important for reinspection of the same specimen. Specifically, we investigate experimentally the role of the laser power density in conjunction with the acquisition times per pixel in a series of repeated iSERS experiments on the same single cell overexpressing the breast cancer tumor marker human epidermal growth factor receptor 2 (HER2). Confocal iSERS mapping experiments were guided by wide-field fluorescence microscopy for selecting the regions of interest. We demonstrate that the combination of ca. a 1-2 mW laser power (40× objective, NA 0.6), 50 ms acquisition time per pixel and a high EM-CCD signal gain yields highly reproducible iSERS images in a series of four repeated experiments on the same single cell. In contrast, longer acquisition times (0.8 s, no EM gain) and in particular higher laser power (4 mW up to 18 mW) densities lead to non-reproducible iSERS results due to signal degradation.

Development and Validation of Multiplex Liquid Bead Array Assay for the Simultaneous Expression of 14 Genes in Circulating Tumor Cells

Liquid biopsy, based on the molecular information extracted from circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), offers the possibility to characterize the evolution of a solid tumor in real time and is highly important for diagnostic and therapeutic purposes. The aim of the present study was the development and validation of a novel liquid bead array methodology for the molecular characterization of CTCs and its application in breast cancer. In the present study we developed and evaluated a multiplex polymerase chain reaction (PCR)-coupled liquid bead array (MLBA) assay for studying simultaneously the expression of 14 genes in CTCs. The 14-gene MLBA assay is characterized by high analytical specificity, sensitivity, and reproducibility. The analytical performance of the 14-gene MLBA assay was compared with a commercially available test (AdnaTest BreastCancer, Qiagen, Germany) and our previously described multiplex quantitative reverse transcription PCR (RT-qPCR) assays. The developed assay has the potential to be further expanded in order to include up to 100 gene targets. The assay is highly specific for each target gene and is not affected by the numerous primers and probes used for multiplexing; hence, it constitutes a sample-, cost-, and time-saving analysis.

Cell-Free DNA Variant Sequencing Using CTC-Depleted Blood for Comprehensive Liquid Biopsy Testing in Metastatic Breast Cancer

Liquid biopsy analytes such as cell-free DNA (cfDNA) and circulating tumor cells (CTCs) exhibit great potential for personalized treatment. Since cfDNA and CTCs are considered to give additive information and blood specimens are limited, isolation of cfDNA and CTC in an "all from one tube" format is desired. We investigated whether cfDNA variant sequencing from CTC-depleted blood (CTC-depl. B; obtained after positive immunomagnetic isolation of CTCs (AdnaTest EMT-2/Stem Cell Select, QIAGEN)) impacts the results compared to cfDNA variant sequencing from matched whole blood (WB). Cell-free DNA was isolated using matched WB and CTC-depl. B from 17 hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer patients (QIAamp MinElute ccfDNA Kit, QIAGEN). Cell-free DNA libraries were constructed (customized QIAseq Targeted DNA Panel for Illumina, QIAGEN) with integrated unique molecular indices. Sequencing (on the NextSeq 550 platform, Illumina) and data analysis (Ingenuity Variant Analysis) were performed. RNA expression in CTCs was analyzed by multimarker quantitative PCR. Cell-free DNA concentration and size distribution in the matched plasma samples were not significantly different. Seventy percent of all variants were identical in matched WB and CTC-depl. B, but 115/125 variants were exclusively found in WB/CTC-depl. B. The number of detected variants per patient and the number of exclusively detected variants per patient in only one cfDNA source did not differ between the two matched cfDNA sources. Even the characteristics of the exclusively detected cfDNA variants in either WB or CTC-depl. B were comparable. Thus, cfDNA variants from matched WB and CTC-depl. B exhibited no relevant differences, and parallel isolation of cfDNA and CTCs from only 10 mL of blood in an "all from one tube" format was feasible. Matched cfDNA mutational and CTC transcriptional analyses might empower a comprehensive liquid biopsy analysis to enhance the identification of actionable targets for individual therapy strategies.

Abstract P6-09-08: High circulating levels of Periostin are associated with a poor survival in primary, non-metastatic breast cancer patients

Background: Periostin, also known as osteoblast-specific factor OSF-2, functions as a ligand for integrins to support adhesion and migration of tumor cells which leads to increased cell survival, invasion, angiogenesis and metastasis in different cancer types including breast cancer (BC). Assuming that metastasis requires a dissemination of tumor cells, associated with worse outcome in BC, the aim of this study was to determine the expression of Periostin in blood samples of patients with primary, non-metastatic BC and to correlate the results with clinical parameters including the presence of disseminated tumor cells (DTCs) in the bone marrow (BM), survival and the risk of developing metastatic disease.

Patients and Methods: BM and blood sampling were performed before surgery in an adjuvant setting in 509 patients with first diagnosis of BC between Aug 2006 and Dec 2009. Two BM aspirates were analyzed for DTCs using density centrifugation followed by immunocytochemistry applying the pan-cytokeratin antibody A45-B/B3. Blood was collected from each patient and Periostin serum levels were measured by ELISA (Biomedica, Vienna, Austria).

Results: Periostin levels were detectable (504.8 ± 178.7 pmol/l) in all BC patients. There were no significant differences between serum Periostin levels when stratifying according to tumor stage, lymph node involvement or grading. Periostin levels were significantly increased in women above the age of 60 (468.6±166.6 pmol/l vs. 540.1±184.2 pmol/l; p&lt;0.0001) and significantly enhanced in postmenopausal compared to peri- or premenopausal women (p&lt;0.05 and p&lt;0.001, respectively). No differences were observed between DTC-positive and DTC-negative patients. When separating patients according to high (top 50%) or low (low 50%) Periostin levels, patients with low Periostin levels had a significantly shorter BC specific survival (HR 0.61; 95%CI 0.39-0.96; p=0.03).

Conclusion: In summary, while Periostin levels were unchanged in patients with and without DTCs, high levels of Periostin were associated with a poorer BC specific survival. These results warrant further studies on the role of Periostin in BC.

Citation Format: Hoffmann O, Goebel A, Bittner A-K, Rauner M, Hofbauer LC, Kimmig R, Kasimir-Bauer S, Rachner TD. High circulating levels of Periostin are associated with a poor survival in primary, non-metastatic breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-08.

Abstract P4-01-10: The analysis of cell-free DNA and circulating tumor cells from one blood tube might empower treatment decisions in metastatic breast cancer patients

Background: The detection and characterization of circulating tumor cells (CTCs) as one of the analytes in liquid biopsy has been considered as surrogate marker to improve treatment decisions in metastatic breast cancer (MBC). In addition, cell-free tumor DNA (ctDNA) released by tumor cells and harboring tumor-associated variants is further discussed to give additional information for therapeutic options. Thus, CTC and ctDNA analysis from the same blood tube is desired. To test usability of plasma, generated after CTC isolation from whole blood for ctDNA analysis, we analyzed ctDNA from 42 hormone receptor-positive/HER2-negative MBC patients (pts) for the detection of tumor-associated variants (plasma isolated straight from whole blood) and compared the results for similarities and differences of the detected variants in a subgroup of these pts to those, obtained from plasma generated after CTC selection (taken from a separate tube).

Methods: 4 ml plasma of all MBC pts and 4 ml plasma obtained after immunomagnetic isolation of CTCs from 2x5ml blood [AdnaTest EMT-2/Stem Cell Select (n=17pts) followed by multimarker qPCR] were used for the analysis of cell-free DNA (cfDNA) applying the QIAamp MinElute ccfDNA Kit. A total of 30ng - 60ng cfDNA was applied for library construction using the QIAseq Targeted DNA Panel for Illumina with integrated unique molecular identifiers. Sequencing was executed on the NextSeq® 500 platform (Illumina, US). Data were analyzed using the QIAseq Targeted Sequencing Data Analysis Portal, the Biomedical Genomics Workbench and the Ingenuity Variant Analysis. All materials used were manufactured by QIAGEN, Germany.

Results: In the total cohort of 42 pts, most variants of all analyzed genes were detected in the MUC16 gene (31.2%). ERBB2, EGFR and AR (androgen receptor) also showed high numbers of variants (11.6%, 11.0% and 8.9%, respectively) with a majority detected pathogenic variants (47.7%) in AR. 92% of all detected variants showed an allele frequency of &lt;5% and some of the detected MUC16, ERBB2 and AR mutations significantly correlated with overall survival. Comparing the plasma results from a separate blood draw with the results from plasma samples after CTC selection in a subgroup of 17/42 pts, no significant difference was found for cfDNA concentration but variability within the cohort. Whereas the variant comparison of ctDNA isolated from both plasma sources showed great concordance, additional variants (around 15%) were exclusively found in one of the two matched samples. Interestingly, in the variant population exclusively found in ctDNA isolated after CTC isolation, the relative amount of pathogenic variants was increased compared to the variant fraction only found in ctDNA from plasma of a separate blood tube. Results obtained for frequently overexpressed CTC transcripts in this subgroup included genes involved in the PI3K signaling pathway as well as ERBB2 and ERBB3 in about 30% of the pts.

Conclusion: We here present a feasible workflow for CTC and ctDNA evaluation for expression and mutation analysis from the same blood sample. These data emphasize that the use of different liquid biopsy analytes can empower treatment decisions of MBC pts in the future.

Citation Format: Kasimir-Bauer S, Bittner A-K, Hoffmann O, Hauch S, Sprenger-Haussels M, Storbeck M, Benyaa K, Hahn P, Mach P, Tewes M, Kimmig R, and Keup C. The analysis of cell-free DNA and circulating tumor cells from one blood tube might empower treatment decisions in metastatic breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-01-10.

Abstract P6-09-01: In primary, non-metastatic breast cancer patients, increased serum levels of RANKL significantly correlate with tumor cell spread to the bone and the occurrence of bone metastasis whereas high levels of its soluble decoy receptor osteoprotegerin predict poor survival

Background: Receptor activator of nuclear factor kappa-B ligand (RANKL) is an essential protein for osteoclast regulation and its activity is controlled by its soluble decoy receptor osteoprotegerin (OPG). RANKL has been associated with benign as well as malignant bone disease and there is increasing evidence that RANKL may also directly affect breast cancer (BC) progression and metastasis to the bone. Here we assessed serum concentrations of RANKL and OPG in 509 patients with primary, non-metastatic BC and correlated the results with clinical parameters including the presence of disseminated tumor cells (DTCs) in the bone marrow (BM), survival and the risk of developing metastatic disease.

Patients and Methods: Patients with first diagnosis of BC between Aug 2006 and Dec 2009 were included in our study. BM sampling was performed before surgery in an adjuvant setting and two BM aspirates were analyzed for DTCs using density centrifugation followed by immunocytochemistry applying the pan-cytokeratin antibody A45-B/B3. Blood was collected from each patient and sRANKL and OPG levels in the serum were measured by ELISA (Biomedica, Vienna, Austria). Results: Mean serum values for RANKL and OPG were 0.23±0.20 pmol/l and 4.24±1.70 pmol/l, respectively. RANKL levels were significantly lower in women above the age of 60 (p&lt;0.0001) and RANKL/OPG ratios were higher in patients with lymph node involvement (p&lt;0.05). High OPG levels were associated with a higher risk of death from BC (HR 1.94 95%CI 1.23-3.07; p=0.005) and multivariate analyses revealed OPG to be an independent prognostic marker for BC specific survival (p=0.035). DTCs were detected in 207/507 (41%) patients and RANKL levels were 33% higher in DTC-positive patients (p&lt;0.0001). Interestingly, in DTC-negative patients, high RANKL levels were associated with a significantly better BC specific survival compared to low levels (HR 0.524; 95%CI 0.30-0.95; p=0.04). RANKL serum levels were significantly enhanced in patients that developed bone metastases (p=0.01) and patients in the highest quartile of RANKL had a significantly increased risk of developing bone metastases compared to those in the lowest RANKL quartile (HR 4.62, 95%CI 1.49-14.34, p=0.03). Conclusion: Increased OPG levels indicated poor survival and high RANKL significantly associated with an increased risk of developing bone metastases while indicating a positive prognostic marker in DTC-negative patients. These findings warrant further investigation as it may provide a rational for novel diagnostic or therapeutic approaches.

Citation Format: Bittner A-K, Goebel A, Hoffmann O, Rauner M, Hofbauer LC, Kimmig R, Kasimir-Bauer S, Rachner TD. In primary, non-metastatic breast cancer patients, increased serum levels of RANKL significantly correlate with tumor cell spread to the bone and the occurrence of bone metastasis whereas high levels of its soluble decoy receptor osteoprotegerin predict poor survival [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-01.

Abstract GS5-07: International pooled analysis of the prognostic impact of disseminated tumor cells from the bone marrow in early breast cancer: Results from the PADDY study

Introduction

As early breast cancer might relapse even after complete removal of breast and lymphnodes, the disease must persist in secondary sites. The detection of disseminated tumor cells (DTC) in the bone marrow (BM) has been described as a surrogate of residual disease. Various trials showed an impaired prognosis of DTC positive early breast cancer (EBC) patients. The PADDY (Pooled Analysis of DTC Detection in Early Breast Cancer) study is a large international pooled analysis that aimed to assess the prognostic impact of DTC detection in patients with EBC.

Methods

A pre-specified protocol was followed, and centers known to practice BM sampling for DTC detection were contacted for individual patient data. Patients with EBC, with available follow-up data and BM sampling before any anti-cancer treatment were eligible. BM aspirates were collected at the time of primary surgery. DTC were identified by antibody (A45-B/B3, AE1/AE3, 2E11 and E29) staining against cytokeratin. The DTC status was compared to other prognostic factors using the chi-squared test. Univariate log-rank test and multivariate cox regression were used to compare survival of DTC positive versus DTC negative patients.

Results

Individual data from 10,320 patients (11 centers from Europe and USA) were included with a median follow-up of 91 months. Of all patients, 2,823 (27.4 %) were DTC positive. DTC detection was associated with higher tumor grade, higher T stage, nodal positivity, ER and PR negativity, and HER2 positivity (all p&lt;0.001). In univariate analyses, overall, breast cancer specific, disease-free and distant disease-free survival (OS, BCSS, DFS, DDFS) were significantly shorter in DTC positive patients with p-values of &lt;0.001. Multivariate analyses showed the DTC status to be an independent prognostic marker for OS, BCSS, DFS and DDFS with hazard ratios (HR) and 95%-confidence intervals (CI) of 1.23 (95%-CI: 1.06-1.42, p=0.007), 1.38 (95%-CI: 1.11-1.72, p=0.004), 1.29 (95%-CI: 1.10-1.50, p=0.001) and 1.32 (95%-CI: 1.10-1.58, p=0.003), respectively.

Conclusions

Detection of DTC in the bone marrow is an independent prognostic marker in patients with non-metastatic breast cancer. Further studies should investigate the impact of DTC on metastatic cancer progression and their role for clinical decision making.

Citation Format: Hartkopf AD, Brucker SY, Taran F-A, Harbeck N, von Au A, Naume B, Pierga J-Y, Hoffmann O, Beckmann MW, Rydén L, Fehm T, Aft R, Montserrat S, Walter V, Rack B, Schuetz F, Borgen E, Ta M-H, Bittner A-K, Fasching P, Fernö M, Krawczyk N, Weilbaecher K, Margelí M, Hahn M, Jueckstock J, Domschke C, Bidard F-C, Kasimir-Bauer S, Schoenfisch B, Kurt AG, Wallwiener M, Gebauer G, Wallwiener D, Janni W, Pantel K. International pooled analysis of the prognostic impact of disseminated tumor cells from the bone marrow in early breast cancer: Results from the PADDY study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS5-07.

Liquid biopsy in ovarian cancer: recent advances on circulating tumor cells and circulating tumor DNA

Ovarian cancer remains the most lethal disease among gynecological malignancies despite the plethora of research studies during the last decades. The majority of patients are diagnosed in an advanced stage and exhibit resistance to standard chemotherapy. Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) represent the main liquid biopsy approaches that offer a minimally invasive sample collection. Both have shown a diagnostic, prognostic and predictive value in many types of solid malignancies and recent studies attempted to shed light on their role in ovarian cancer. This review is mainly focused on the clinical value of both CTCs and ctDNA in ovarian cancer and, more specifically, on their potential as diagnostic, prognostic and predictive tumor biomarkers.

Dissimilar patterns of tumor-infiltrating immune cells at the invasive tumor front and tumor center are associated with response to neoadjuvant chemotherapy in primary breast cancer

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are described as an important immune modulator in the tumor microenvironment and are associated with breast cancer (BC) outcome. The spatial analysis of TILs and TIL subtype distribution at the invasive tumor front (ITF) and the tumor center (TC) might provide further insights into tumor progression.

METHODS

We analyzed core biopsies from 87 pre-therapeutic BC patients for total TILs and the following subtypes: CD3+, CD4+, CD8+, CD20+ and CD68+ cells in correlation to clinicopathological parameters and disseminated tumor cells (DTCs) in the bone marrow.

RESULTS

TILs and TIL subtypes showed significantly different spatial distribution among both tumor areas. TILs, especially CD3+ T cells were associated with the tumor status and tumor grading. BC patients responding to neoadjuvant chemotherapy had significantly more TILs and CD3+ T cells at the TC. The presence of DTCs after NACT was related to CD4+ infiltration at the TC.

CONCLUSION

The dissimilar spatial association of TILs and TIL subtypes with clinicopathological parameters, NACT response and minimal residual disease underlines the necessity of detailed TIL analysis for a better understanding of immune modulatory processes.

Extracellular vesicle-associated miRNAs in ovarian cancer – design of an integrated NGS-based workflow for the identification of blood-based biomarkers for platinum-resistance

Background

Extracellular vesicle (EV)-associated microRNAs (miRNAs) have been suggested as promising biomarkers for blood-based cancer diagnosis. However, one of the major limitations for the use of EVs with diagnostic purpose is the lack of standardized EV-profiling techniques. In this regard, the objective of our study was to design an integrated next-generation sequencing (NGS)-based workflow for analyzing the signature of EV-associated miRNA in the plasma of platinum-resistant ovarian cancer patients.

Methods

For EV-extraction, different enrichment methods were compared (ExoQuick vs. exoRNeasy). NGS was performed with the Illumina platform.

Results

We established an integrated NGS-based workflow, including EV-enrichment with the ExoQuick system, which resulted in an optimal RNA-yield and consistent small RNA libraries. We applied this workflow in a pilot cohort of clinically documented platinum-sensitive (n=15) vs. platinum-resistant (n=15) ovarian cancer patients, resulting in a panel of mature EV-associated miRNAs (including ovarian cancer associated miR-181a, miR-1908, miR-21, miR-486 and miR-223), which were differentially abundant in the plasma of platinum-resistant patients.

Conclusions

This is the first study, analyzing the profile of EV-associated miRNAs in platinum-resistant ovarian cancer patients. We provide rationale to further validate these miRNA candidates in an independent set of patients, in order to characterize their biomarker potential as predictors for platinum-resistance.