Comparison of assessment of programmed death-ligand 1 (PD-L1) status in triple-negative breast cancer biopsies and surgical specimens

AIMS

Programmed death-ligand 1 (PD-L1) status in triple-negative breast cancer (TNBC) is important for immune checkpoint inhibitor therapies but may vary between different immunohistochemical assays, scorings and the type of specimen used for analysis.

METHODS

We compared the analytical concordance of three clinically relevant PD-L1 assays (VENTANA SP142, VENTANA SP263 and DAKO 22C3 pharmDx) assessing immune cell score (IC), tumour proportion score and combined positive score (CPS) in preoperative biopsies and resection specimens of primary TNBC. PD-L1 expression was scored on virtual whole slide images and compared with expression data from corresponding surgical specimens.

RESULTS

The mean PD-L1 positivity in TNBC biopsies defined as IC ≥1% and CPS ≥1 ranged between 11% and 61% with the lowest positivity for SP142 and highest for SP263. The corresponding surgical specimens showed overall higher positivity rates (53%-75%). When comparing biopsies with surgical specimens, the agreement for PD-L1 positivity with SP263 and 22C3 at IC score ≥1% and CPS ≥1 was fair (kappa 0.47-0.52) and poor for SP142 (kappa 0.15-0.19). Using CPS ≥10 cut-off, the agreement for SP263 was excellent (kappa 0.751) but poor for 22C3 (kappa 0.261). Spearman correlation coefficients ranged between 0.489 and 0.75 indicating a generally moderate to strong correlation between biopsies and surgical specimens for all assays and scores.

CONCLUSIONS

We demonstrate high accordance between biopsies and surgical specimens for SP263 and 22C3 scoring but less for SP142. Generally, biopsies are suitable for PD-L1 testing in TNBC but the appropriate assay, scoring and cut-off must be considered.

Independent Tissue-Based Biomarkers in Endometrioid Endometrial Cancer: Tumor Budding in Microsatellite Instability and WHO Grading in Copy-Number-Low Patients

The molecular characterization of endometrial endometrioid adenocarcinomas has provided major advances in its prognostic stratification. However, risk assessment of microsatellite instability (MSI) and copy-number (CN)-low cases remains a challenge. Thus, we aimed to identify tissue-based morphologic biomarkers that might help in the prognostic stratification of these cases. Histomorphologic parameters (WHO grading, tumor budding (TB), tumor-stroma ratio (as a quantitative description of stromal desmoplasia), tumor-infiltrating lymphocytes (TIL), "microcystic, elongated, fragmented" (MELF) pattern) were analyzed in resection specimens of the TCGA-UCEC cohort (n = 228). For each quantitative parameter, a two-tiered system was developed utilizing systematically determined cutoffs. Associations with survival outcomes were calculated in univariate and multivariate analysis and validated in two independent cohorts. In MSI tumors, only TB remained an independent prognostic factor. TB (≥3 buds/high-power field) was associated with inferior outcomes and with lymph node metastases. The prognostic significance of TB was confirmed in two validation cohorts. For CN-low tumors, established grading defined by the WHO was independently prognostic with inferior outcomes for high-grade tumors. The evaluation of TB might help in identifying MSI-patients with unfavorable prognosis who, e.g., could benefit from lymphadenectomy. WHO-based grading facilitates independent prognostic stratification of CN-low endometrioid adenocarcinomas. Therefore, we propose the utilization of TB and WHO-based grading, two tissue-based and easy-to-assess biomarkers, in MSI/CN-low endometrial carcinomas for improved clinical management.

The immunohistochemical expression of GPER and classical sex hormone receptors differs in adenomyosis and eutopic endometrium

G protein-coupled estrogen receptor (GPER) has been found to be an important key regulator in the homeostasis of sex hormone-dependent human cells. The aim of this study was to compare the expression of GPER, estrogen receptor alpha (ER-α), estrogen receptor beta (ER-β) and progesterone receptor (PR) in adenomyosis, eutopic endometrium from the same patients, and eutopic endometrium from patients without adenomyosis. Immunohistochemical analysis of GPER, ER-α, ER-β and PR was performed to assess the expression levels on samples of hysterectomies using tissue microarrays. 73 adenomyotic tissue probes and corresponding eutopic endometrial specimens, as well as 48 samples of eutopic endometrial control specimens from patients without adenomyosis were included in this study. Mean age of the women with adenomyosis was 51.7 (SD ± 11.1) and 65.8% were premenopausal. We found a higher nuclear stromal expression of GPER in eutopic endometrium of patients with adenomyosis in comparison to control endometrium (p < 0.001). Comparing adenomyosis to eutopic endometrium of patients with adenomyosis and to control, there was a lower expression of nuclear GPER in epithelial cells (p < 0.001 and p = 0.048, respectively). Lower epithelial nuclear ER-α in adenomyosis and higher epithelial nuclear ER-β in eutopic endometrium of patients with adenomyosis was found in comparison to control endometrium (p = 0.008 and p = 0.017, respectively). This study showed a significant difference in the immunohistochemical expression of GPER in adenomyosis compared to eutopic endometrium of the same patients and to endometrium of control group. GPER in adenomyosis may be a potential therapeutic target for selective agonists and antagonists.

Characterization of Hormone Receptor and HER2 Status in Breast Cancer Using Mass Spectrometry Imaging

Immunohistochemical evaluation of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 status stratify the different subtypes of breast cancer and define the treatment course. Triple-negative breast cancer (TNBC), which does not register receptor overexpression, is often associated with worse patient prognosis. Mass spectrometry imaging transcribes the molecular content of tissue specimens without requiring additional tags or preliminary analysis of the samples, being therefore an excellent methodology for an unbiased determination of tissue constituents, in particular tumor markers. In this study, the proteomic content of 1191 human breast cancer samples was characterized by mass spectrometry imaging and the epithelial regions were employed to train and test machine-learning models to characterize the individual receptor status and to classify TNBC. The classification models presented yielded high accuracies for estrogen and progesterone receptors and over 95% accuracy for classification of TNBC. Analysis of the molecular features revealed that vimentin overexpression is associated with TNBC, supported by immunohistochemistry validation, revealing a new potential target for diagnosis and treatment.

Interassay and interobserver comparability study of four programmed death-ligand 1 (PD-L1) immunohistochemistry assays in triple-negative breast cancer

Different immunohistochemical programmed death-ligand 1 (PD-L1) assays and scorings have been reported to yield variable results in triple-negative breast cancer (TNBC). We compared the analytical concordance and reproducibility of four clinically relevant PD-L1 assays assessing immune cell (IC) score, tumor proportion score (TPS), and combined positive score (CPS) in TNBC. Primary TNBC resection specimens (n = 104) were stained for PD-L1 using VENTANA SP142, VENTANA SP263, DAKO 22C3, and DAKO 28–8. PD-L1 expression was scored according to guidelines on virtual whole slide images by four trained readers.

The mean PD-L1 positivity at IC-score ≥1% and CPS ≥1 ranged between 53% and 75% with the highest positivity for SP263 and comparable levels for 22C3, 28–8, and SP142. Inter-assay agreement was good between 28–8 and 22C3 across all scores and cut-offs (kappa 0.68–0.74) and for both assays with SP142 at IC-score ≥1% and CPS ≥1 (kappa 0.61–0.67). The agreement between SP263 and all other assays was substantially lower for all scores. Inter-reader agreement for each assay was good to excellent for IC-score ≥1% (kappa 0.73–0.78) and CPS ≥1 (kappa 0.68–0.74), fair to good for CPS ≥10 (kappa 0.52–0.67) and TPS ≥1% (kappa 0.53–0.72). The percentage of overlapping cases in the positive/negative category was >90% between IC-score ≥1% and CPS ≥1 but below when comparing IC-score ≥1% with CPS ≥10. We demonstrate an overall good inter-reader agreement for all PD-L1 assays in TNBC along with assay specific differences in positivity and concordances, which may aid to select the right test strategy in routine diagnostics.

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Different PD-L1 IHC assays and scorings may show variable results in TNBC.

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Overall good assay concordance between SP142, 22C3, and 28–8 at IC-score 1%.

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Overall good assay concordance between SP142, 22C3, and 28–8 at CPS 1.

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SP142 is less optimal for CPS assessment at higher cut-offs.

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SP263 assay is not interchangeable with the other three PD-L1 assays.

The Chemokine CX3CL1 Improves Trastuzumab Efficacy in HER2 Low-Expressing Cancer In Vitro and In Vivo

A crucial mode of action of trastuzumab is the labeling of HER2-positive (HER2⁺) tumor cells for the eradication by natural killer (NK) cells, a process called antibody-dependent cellular cytotoxicity (ADCC). However, despite widespread HER2 expression among cancer entities, only a fraction, with robust HER2 overexpression, benefits from trastuzumab therapy. ADCC requires both sufficient lymphocytic infiltration and close binding of the immune cells to the antibody-tagged tumor cells. We hypothesized that the chemokine CX3CL1 could improve both processes, as it is synthesized as a membrane-bound, adhesive form that is eventually cleaved into a soluble, chemotactic protein. Here, we show that CX3CL1 overexpression is a positive prognostic marker in breast cancer. CX3CL1 overexpression attracted tumor-suppressive lymphocytes, including NK cells, and inhibited tumor growth and lung metastasis in the syngeneic 4T1 breast cancer mouse model. In HER2⁺ SKBR3, MDA-MB-453, and HT-29 tumor cells, CX3CL1 overexpression increased NK cell-mediated cytotoxicity in vitro and acted synergistically with trastuzumab. Even though CX3CL1 did not further improve trastuzumab efficacy in vivo in the trastuzumab-sensitive MDA-MB-453 model, it compensated for NK-cell depletion and prolonged survival. In the HER2 low-expressing HT-29 model, however, CX3CL1 overexpression not only prolonged survival time but also overcame trastuzumab resistance in a partly NK cell-dependent manner. Taken together, these findings identify CX3CL1 as a feasible pharmacologic target to enable trastuzumab therapy in HER2 low-expressing cancers and render it a potential predictive biomarker to determine therapy responders.

A requirement for p120-catenin in the metastasis of invasive ductal breast cancer

We report here the effects of targeted p120-catenin (encoded by CTNND1; hereafter denoted p120) knockout (KO) in a PyMT mouse model of invasive ductal (mammary) cancer (IDC). Mosaic p120 ablation had little effect on primary tumor growth but caused significant pro-metastatic alterations in the tumor microenvironment, ultimately leading to a marked increase in the number and size of pulmonary metastases. Surprisingly, although early effects of p120-ablation included decreased cell-cell adhesion and increased invasiveness, cells lacking p120 were almost entirely unable to colonized distant metastatic sites in vivo The relevance of this observation to human IDC was established by analysis of a large clinical dataset of 1126 IDCs. As reported by others, p120 downregulation in primary IDC predicted worse overall survival. However, as in the mice, distant metastases were almost invariably p120 positive, even in matched cases where the primary tumors were p120 negative. Collectively, our results demonstrate a strong positive role for p120 (and presumably E-cadherin) during metastatic colonization of distant sites. On the other hand, downregulation of p120 in the primary tumor enhanced metastatic dissemination indirectly via pro-metastatic conditioning of the tumor microenvironment.

A multicentre analytical comparison study of inter-reader and inter-assay agreement of four programmed death-ligand 1 immunohistochemistry assays for scoring in triple-negative breast cancer

AIMS

Studies in various cancer types have demonstrated discordance between results from different programmed death-ligand 1 (PD-L1) assays. Here, we compare the reproducibility and analytical concordance of four clinically developed assays for assessing PD-L1-positivity in tumour-infiltrating immune cells in the tumour area (PD-L1-IC-positivity) in triple-negative breast cancer (TNBC).

METHODS AND RESULTS

Primary TNBC resection specimens (n = 30) were selected based on their PD-L1-IC-positivity per VENTANA SP142 (<1%: 15 cases; 1-5%: seven cases; >5%: eight cases). Serial histological sections were stained for PD-L1 using VENTANA SP142, VENTANA SP263, DAKO 22C3 and DAKO 28-8. PD-L1-IC-positivity and tumour cell expression (≥1 versus <1%) were scored by trained readers from seven sites using online virtual microscopy. The adjusted mean of PD-L1-IC-positivity for SP263 (7.8%) was significantly higher than those for the other three assays (3.7-4.9%). Differences in adjusted means were statistically significant between SP263 and the other three assays (P < 0.0001) but not between the three remaining assays when excluding SP263 (P = 0.0961-0.6522). Intra-class correlation coefficients revealed moderate-to-strong inter-reader agreement for each assay (0.460-0.805) and poor-to-strong inter-assay agreement for each reader (0.298-0.678) on PD-L1-IC-positivity.

CONCLUSIONS

In this first multicentre study of different PD-L1 assays in TNBC, we show that PD-L1-IC-positivity for SP142, 22C3 and 28-8 was reproducible and analytically concordant, indicating that these three assays may be analytically interchangeable. The relevance of the higher PD-L1-IC-positivity for SP263 should be further investigated.

First prospective outcome data for the second-generation multigene test Endopredict in ER-positive/HER2-negative breast cancer

Purpose

Prospectively collected outcome data of patients (pts) whose adjuvant systemic therapy recommendation was based on the clinico-molecular test EndoPredict^® (EP) are presented.

Methods

Pts with ER-positive, HER2-negative early breast cancer with 0–3 positive lymph nodes were enrolled. The EP was carried out on all tumor samples. Pts were evaluated for treatment compliance, local recurrence, distant metastases and overall survival. Censored time-to-event outcomes were analysed by Cox proportional hazards models. Additional estimates of the event-free-survival were calculated by the Kaplan–Meier method. Hypothesis testing was conducted on two-sided exploratory 5% significance levels.

Results

373 consecutive pts were enrolled. EP classified 238 pts (63.8%) as low risk and 135 pts (36.2%) as high risk. Median follow-up was 41.6 months. Risk for disease recurrence or death in EPclin high-risk patients was twofold higher in comparison with EPclin low-risk patients (hazard ratio (HR) 2.05 (95% CI 0.85–4.96; p = 0.110). Patients with EPclin high risk were at significant higher risk of distant metastases than patients with EPclin low risk (HR 5.18; 95% CI 1.04–25.74; p = 0.0443). EPclin high-risk patients who actually underwent adjuvant CTX had a 3-year-DFS of 96.3% (95% CI 92.2–100) in contrast to EPclin high-risk patients without CTX (3-year-DFS: 91.5% (95% CI 82.7–100%); HR 0.32; 95% CI 0.10–1.05; p = 0.061).

Conclusion

These first prospective outcome results show that EP, in clinical routine, is a valid clinico-molecular test, to predict DFS and to guide decision of adjuvant CTX use in ER-positive, HER2-negative early breast cancer pts with 0–3 positive lymph nodes. Adjuvant CTX seems to be beneficial for EPclin high-risk patients.

Loss of MDC1 in Endometrial Carcinoma Is Associated With Loss of MRN Complex and MMR Deficiency

AIM

To evaluate the frequency of loss of mediator of DNA damage checkpoint protein 1 (MDC1) protein expression in endometrial cancer (EC) and to determine whether loss of MDC1 is associated with certain clinicopathological parameters.

MATERIALS AND METHODS

MDC1 expression was examined in 426 samples of EC. The nuclear immunoreactivity of the protein was defined as: negative, weak, moderate and strong.

RESULTS

Loss of MDC1 expression (defined as negative nuclear staining) was found in 8.9% (38/426) of ECs and was significantly associated with the loss of MRE11 homolog, double-strand break repair nuclease, RAD50 double-strand break repair protein and nibrin complex components. In addition, loss of expression of MDC1 showed a significant correlation with any mismatch repair deficiency, with endometrioid histological subtype and low tumour grading.

CONCLUSION

Based on these findings, we suggest that MDC1 loss frequently occurs in ECs with microsatellite instability. Due to deficient homologous recombination DNA repair, MDC1-negative ECs might show an increased sensitivity to poly(ADP-ribose) polymerase-inhibitory therapy.

Risk stratification in luminal-type breast cancer: Comparison of Ki-67 with EndoPredict test results

OBJECTIVES

Adjuvant chemotherapy decision in patients with hormone receptor positive, HER2 negative breast cancer (BC) is challenging. Ki-67 is widely used for adjuvant therapy decision in BC. The multigene assay EndoPredict (EP) has shown to provide valid and additional information about the risk of recurrence compared to traditional pathological factors. In this study, we compared Ki-67 with EP assay generated risk groups.

METHODS

We analyzed the results from prospective EP testing (n = 373) and tumor proliferation assessed by Ki-67 staining in luminal breast cancer. We statistically investigated the association of both parameters and probed for equivalence in risk stratification.

RESULTS

Evaluation of Ki-67 was feasible in 307 (82%) BC specimens with known EP test results. The EPscore (now called 12-gene molecular score) delineated 140 low and 167 high scores. After combining the EPscore with pathological tumor stage and nodal status, we received 203 EPclin low-risk and 104 EPclin high-risk classifications. EPscore and EPclin were significantly associated with Ki-67 indices and tumor grade (p < 0.001). Overall, we observed a moderate correlation between Ki-67 and the EPscore (r = 0.63) as well as the EPclin score (r = 0.59).

CONCLUSION

Ki-67 values above 25% partly overlap with EP test results and therefore indicate a high-risk profile. In these cases, the additional prognostic information from EP testing might be rather low. However, low and intermediate Ki-67 values (less than 25%) alone were not reliable in predicting a low risk EP profile, indicating that EP testing is useful in this subgroup.

Clinical performance of an analytically validated assay in comparison to microarray technology to assess PITX2 DNA-methylation in breast cancer

Significant evidence has accumulated that DNA-methylation of the paired-like homeodomain transcription factor 2 (PITX2) gene can serve as a prognostic and predictive biomarker in breast cancer. PITX2 DNA-methylation data have been obtained so far from microarray and polymerase chain reaction (PCR)-based research tests. The availability of an analytically validated in vitro methylation-specific real-time PCR assay format (therascreen PITX2 RGQ PCR assay) intended for the determination of the percent methylation ratio (PMR) in the (PITX2) promoter 2 prompted us to investigate whether the clinical performance of these different assay systems generate comparable clinical outcome data. Mathematically converted microarray data of a previous breast cancer study (n = 204) into PMR values leads to a PITX2 cut-off value at PMR 14.73. Recalculation of the data to experimentally equivalent PMRs with the PCR PITX2 assay leads to a cut-off value at PMR 12 with the highest statistical significance. This cut-off predicts outcome of high-risk breast cancer patients to adjuvant anthracycline-based chemotherapy (n = 204; Hazard Ratio 2.48; p < 0.001) comparable to microarray generated results (n = 204; Hazard ratio 2.32; p < 0.0001). The therascreen PITX2 RGQ PCR assay is an analytically validated test with high reliability and robustness and predicts outcome of high-risk breast cancer patients to anthracycline-based chemotherapy.

Clinical Validation of PITX2 DNA Methylation to Predict Outcome in High-Risk Breast Cancer Patients Treated with Anthracycline-Based Chemotherapy

Background: Breast cancer patients at high risk for recurrence are treated with anthracycline-based chemotherapy, but not all patients do equally benefit from such a regimen. To further improve therapy decision-making, biomarkers predicting outcome are of high unmet medical need. Methods: The percent DNA methylation ratio (PMR) of the promoter gene coding for the Paired-like homeodomain transcription factor 2 (PITX2) was determined by a validated methylation-specific real-time polymerase chain reaction (PCR) test. The multicenter study was conducted in routinely collected archived formalin-fixed paraffin-embedded (FFPE) tissue from 205 lymph node-positive breast cancer patients treated with adjuvant anthracycline-based chemotherapy. Results: The cut-off for the PITX2 methylation status (PMR = 12) was confirmed in a randomly selected cohort (n = 60) and validated (n = 145) prospectively with disease-free survival (DFS) at the 10-year follow-up. DFS was significantly different between the PMR ≤ 12 versus the PMR > 12 group with a hazard ratio (HR) of 2.74 (p < 0.001) in the validation cohort and also for the patient subgroup treated additionally with endocrine therapy (HR 2.47; p = 0.001). Conclusions: Early-stage lymph node-positive breast cancer patients with low PITX2 methylation do benefit from adjuvant anthracycline-based chemotherapy. Patients with a high PITX2 DNA methylation ratio, approximately 30%, show poor outcome and should thus be considered for alternative chemotherapy regimens.

PET imaging of chemokine receptor CXCR4 in patients with primary and recurrent breast carcinoma

Background

CXCR4 is a chemokine receptor frequently overexpressed in invasive breast cancer that has been shown to play a major role in signaling pathways involved in metastasis. The aim of this retrospective analysis was to assess the diagnostic performance of CXCR4-directed PET imaging in patients with breast cancer using the recently introduced CXCR4-targeted PET probe ⁶⁸Ga-Pentixafor.

Results

Thirteen patients with first diagnosis of breast cancer, four patients with recurrent disease after primary breast cancer, and one patient with axillary lymph node metastasis of unknown primary underwent CXCR4-targeted PET imaging using ⁶⁸Ga-Pentixafor. Maximum standardized uptake values (SUVmax) and tumor-to-background (T/B) ratios of tumor lesions were measured and compared with pathological prognostic factors and molecular subtypes. ¹⁸F-FDG PET/CT images were available in 8/18 cases and were compared semi-quantitatively. Comparison with CXCR4 expression determined by immunohistochemistry was performed in 7/18 patients.

Nine of 13 primary breast cancers were visually detectable on ⁶⁸Ga-Pentixafor PET images (mean SUVmax of 3.0). The visually undetectable lesions included both cases of invasive lobular carcinoma (ILC) and two cases of invasive carcinoma of no special type (NST) without any hormone receptor and HER2 expression (triple negative). Metastases of recurrent breast cancer and unknown primary cancer were visually detectable in all five cases, exhibiting a mean SUVmax of 3.5. ¹⁸F-FDG PET demonstrated higher SUVmax in all patients compared to ⁶⁸Ga-Pentixafor PET. A correlation between SUVmax obtained from ⁶⁸Ga-Pentixafor PET and prognostic factors including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) status, proliferation index, tumor grade, or molecular subtypes was not observed.

Conclusions

CXCR4-directed PET imaging in patients with primary and recurrent breast cancer is feasible; however, tumor detectability is significantly lower compared to ¹⁸F-FDG PET. Moreover, we did not find any correlation between aforementioned prognostic factors of breast cancer and CXCR4-targeted tracer accumulation. Based on these results in a small patient cohort, CXCR4-targeted PET imaging does not seem to be suitable as a general diagnostic tool for imaging of breast cancer. Future CXCR4 imaging studies should investigate whether this modality might be useful in more specific applications, e.g., in therapeutic approaches especially under the view of current developments in targeted immune cell and immune checkpoint inhibitory therapy.

Introducing a novel highly prognostic grading scheme based on tumour budding and cell nest size for squamous cell carcinoma of the uterine cervix

A novel histopathological grading system based on tumour budding and cell nest size has recently been shown to outperform conventional (WHO‐based) grading algorithms in several tumour entities such as lung, oral, and oesophageal squamous cell carcinoma (SCC) in terms of prognostic patient stratification. Here, we tested the prognostic value of this innovative grading approach in two completely independent cohorts of SCC of the uterine cervix. To improve morphology‐based grading, we investigated tumour budding activity and cell nest size as well as several other histomorphological factors (e.g., keratinization, nuclear size, mitotic activity) in a test cohort (n = 125) and an independent validation cohort (n = 122) of cervical SCC. All parameters were correlated with clinicopathological factors and patient outcome. Small cell nest size and high tumour budding activity were strongly associated with a dismal patient prognosis (p < 0.001 for overall survival [OS], disease‐specific survival, and disease‐free survival; test cohort) in both cohorts of cervical SCC. A novel grading algorithm combining these two parameters proved to be a highly effective, stage‐independent prognosticator in both cohorts (OS: p < 0.001, test cohort; p = 0.001, validation cohort). In the test cohort, multivariate statistical analysis of the novel grade revealed that the hazard ratio (HR) for OS was 2.3 for G2 and 5.1 for G3 tumours compared to G1 neoplasms (p = 0.010). In the validation cohort, HR for OS was 3.0 for G2 and 7.2 for G3 tumours (p = 0.012).

In conclusion, our novel grading algorithm incorporating cell nest size and tumour budding allows strongly prognostic histopathological grading of cervical SCC superior to WHO‐based grading. Therefore, our data can be regarded as a cross‐organ validation of previous results demonstrated for oesophageal, lung, and oral SCC. We suggest this grading algorithm as an additional morphology‐based parameter for the routine diagnostic assessment of this tumour entity.

PITX2 DNA-methylation predicts response to anthracycline-based adjuvant chemotherapy in triple-negative breast cancer patients

Triple-negative breast cancer (TNBC) constitutes a heterogeneous breast cancer subgroup with poor prognosis; survival rates are likely to be lower with TNBC compared to other breast cancer subgroups. For this disease, systemic adjuvant chemotherapy regimens often yield suboptimal clinical results. To improve treatment regimens in TNBC, identification of molecular biomarkers may help to select patients for individualized adjuvant therapy. Evidence has accumulated that determination of the methylation status of the PITX2 gene provides a predictive value in various breast cancer subgroups, either treated with endocrine-based therapy or anthracycline-containing chemotherapy. To further explore the validity of this novel predictive candidate biomarker, in the present exploratory retrospective study, determination of the PITX2 DNA-methylation status was assessed for non-metastatic TNBC patients treated with adjuvant anthracycline-based chemotherapy by molecular analysis of breast cancer tissues. The PITX2 DNA-methylation status was determined in fresh-frozen tumor tissue specimens (n=56) by methylation-specific qRT-PCR (qMSP) and the data related to disease-free and overall survival, applying an optimized DNA-methylation score of 6.35%. For non-metastatic TNBC patients treated with adjuvant systemic anthracycline-based chemotherapy, a low PITX2 DNA-methylation status (<6.35) defines TNBC patients with poor disease-free and overall survival. Univariate and multivariate analyses demonstrate the statistically independent predictive value of PITX2 DNA-methylation. For non-metastatic TNBC patients, selective determination of the PITX2 DNA-methylation status may serve as a cancer biomarker for predicting response to anthracycline-based adjuvant chemotherapy. The assay based on methylation of the PIXT2 gene can be applied to frozen and routinely available formalin-fixed, paraffin-embedded (FFPE) breast cancer tumor tissues that will not only define those TNBC patients who may benefit from anthracycline-based chemotherapy but also those who should be spared the necessity of such potentially toxic treatment. Such patients should be allocated to alternative treatment options.

Tumour-infiltrating lymphocytes and prognosis in different subtypes of breast cancer: a pooled analysis of 3771 patients treated with neoadjuvant therapy

BACKGROUND

Tumour-infiltrating lymphocytes (TILs) are predictive for response to neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) and HER2-positive breast cancer, but their role in luminal breast cancer and the effect of TILs on prognosis in all subtypes is less clear. Here, we assessed the relevance of TILs for chemotherapy response and prognosis in patients with TNBC, HER2-positive breast cancer, and luminal-HER2-negative breast cancer.

METHODS

Patients with primary breast cancer who were treated with neoadjuvant combination chemotherapy were included from six randomised trials done by the German Breast Cancer Group. Pretherapeutic core biopsies from 3771 patients included in these studies were assessed for the number of stromal TILs by standardised methods according to the guidelines of the International TIL working group. TILs were analysed both as a continuous parameter and in three predefined groups of low (0-10% immune cells in stromal tissue within the tumour), intermediate (11-59%), and high TILs (≥60%). We used these data in univariable and multivariable statistical models to assess the association between TIL concentration and pathological complete response in all patients, and between the amount of TILs and disease-free survival and overall survival in 2560 patients from five of the six clinical trial cohorts.

FINDINGS

In the luminal-HER2-negative breast cancer subtype, a pathological complete response (pCR) was achieved in 45 (6%) of 759 patients with low TILs, 48 (11%) of 435 with intermediate TILs, and 49 (28%) of 172 with high TILs. In the HER2-positive subtype, pCR was observed in 194 (32%) of 605 patients with low TILs, 198 (39%) of 512 with intermediate TILs, and 127 (48%) of 262 with high TILs. Finally, in the TNBC subtype, pCR was achieved in 80 (31%) of 260 patients with low TILs, 117 (31%) of 373 with intermediate TILs, and 136 (50%) of 273 with high TILs (p<0·0001 for each subtype, χ² test for trend). In the univariable analysis, a 10% increase in TILs was associated with longer disease-free survival in TNBC (hazard ratio [HR] 0·93 [95% CI 0·87-0·98], p=0·011) and HER2-positive breast cancer (0·94 [0·89-0·99], p=0·017), but not in luminal-HER2-negative tumours (1·02 [0·96-1·09], p=0·46). The increase in TILs was also associated with longer overall survival in TNBC (0·92 [0·86-0·99], p=0·032), but had no association in HER2-positive breast cancer (0·94 [0·86-1·02], p=0·11), and was associated with shorter overall survival in luminal-HER2-negative tumours (1·10 [1·02-1·19], p=0·011).

INTERPRETATION

Increased TIL concentration predicted response to neoadjuvant chemotherapy in all molecular subtypes assessed, and was also associated with a survival benefit in HER2-positive breast cancer and TNBC. By contrast, increased TILs were an adverse prognostic factor for survival in luminal-HER2-negative breast cancer, suggesting a different biology of the immunological infiltrate in this subtype. Our data support the hypothesis that breast cancer is immunogenic and might be targetable by immune-modulating therapies. In light of the results in luminal breast cancer, further research investigating the interaction of the immune system with different types of endocrine therapy is warranted.

FUNDING

Deutsche Krebshilfe and European Commission.

Multispectral Optoacoustic Tomography (MSOT) of Human Breast Cancer

Purpose: In a pilot study, we introduce fast handheld multispectral optoacoustic tomography (MSOT) of the breast at 28 wavelengths, aiming to identify high-resolution optoacoustic (photoacoustic) patterns of breast cancer and noncancerous breast tissue.Experimental Design: We imaged 10 female patients ages 48-81 years with malignant nonspecific breast cancer or invasive lobular carcinoma. Three healthy volunteers ages 31-36 years were also imaged. Fast-MSOT was based on unique single-frame-per-pulse (SFPP) image acquisition employed to improve the accuracy of spectral differentiation over using a small number of wavelengths. Breast tissue was illuminated at the 700-970 nm spectral range over 0.56 seconds total scan time. MSOT data were guided by ultrasonography and X-ray mammography or MRI.Results: The extended spectral range allowed the computation of oxygenated hemoglobin (HBO₂), deoxygenated hemoglobin (HB), total blood volume (TBV), lipid, and water contributions, allowing first insights into in vivo high-resolution breast tissue MSOT cancer patterns. TBV and Hb/HBO₂ images resolved marked differences between cancer and control tissue, manifested as a vessel-rich tumor periphery with highly heterogeneous spatial appearance compared with healthy tissue. We observe significant TBV variations between different tumors and between tumors over healthy tissues. Water and fat lipid layers appear disrupted in cancer versus healthy tissue; however, offer weaker contrast compared with TBV images.Conclusions: In contrast to optical methods, MSOT resolves physiologic cancer features with high resolution and revealed patterns not offered by other radiologic modalities. The new features relate to personalized and precision medicine potential. Clin Cancer Res; 23(22); 6912-22. ©2017 AACR.

LACTB is a tumour suppressor that modulates lipid metabolism and cell state

Post-mitotic, differentiated cells exhibit a variety of characteristics that contrast with those of actively growing neoplastic cells, such as the expression of cell-cycle inhibitors and differentiation factors. We hypothesized that the gene expression profiles of these differentiated cells could reveal the identities of genes that may function as tumour suppressors. Here we show, using in vitro and in vivo studies in mice and humans, that the mitochondrial protein LACTB potently inhibits the proliferation of breast cancer cells. Its mechanism of action involves alteration of mitochondrial lipid metabolism and differentiation of breast cancer cells. This is achieved, at least in part, through reduction of the levels of mitochondrial phosphatidylserine decarboxylase, which is involved in the synthesis of mitochondrial phosphatidylethanolamine. These observations uncover a novel mitochondrial tumour suppressor and demonstrate a connection between mitochondrial lipid metabolism and the differentiation program of breast cancer cells, thereby revealing a previously undescribed mechanism of tumour suppression.

Tracking the origin of simultaneous endometrial and ovarian cancer by next-generation sequencing - a case report

Background

Endometrioid adenocarcinoma of the uterus and ovarian endometrioid carcinoma share many morphological and molecular features. Differentiation between simultaneous primary carcinomas and ovarian metastases of an endometrial cancer may be very challenging but is essential for prognostic and therapeutic considerations.

Case Presentation

In the present case study of a 33 year-old patient we used targeted amplicon next-generation re-sequencing for clarifying the origin of synchronous endometrioid cancer of the corpus uteri and the left ovary. The patient developed a metachronous lung metastasis of an endometrioid adenocarcinoma four years after hyster- and adnexectomy, vaginal brachytherapy and treatment with the synthetic steroid tibolone. Removal of the metastasis and megestrol treatment for seven years led to a complete remission.

A total of 409 genes from the Ampliseq Comprehensive Cancer Panel (Ion Torrent, Thermo Fisher) were analysed by next generation sequencing and mutations in 10 genes, including ARID1A, CTNNB1, PIK3CA and PTEN were identified and confirmed by Sanger sequencing. Primary endometrial as well as ovarian cancer showed an identical mutational profile, suggesting the presence of an ovarian metastasis of the endometrial cancer, rather than a simultaneous endometrial and ovarian cancer. The metachronous lung metastasis showed a different mutational profile compared to the primary cancer. Immunohistochemical staining of the corresponding proteins suggested that the tumour development was driven by alterations in the protein function rather than by changes of the protein abundance in the cell.

Conclusions

Our results have demonstrated next generation sequencing as a valuable tool in the differentiation of synchronous primary tumours and metastases, which has an important impact on the clinical decision making process. Similar to breast cancer, targeted therapies based on mutational tumour profiling will become increasingly important in endometrial and ovarian cancer. In summary, our results support the usage of next generation sequencing as a supplementary diagnostic tool, assisting in personalized precision medicine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3054-6) contains supplementary material, which is available to authorized users.

Lack of MRE11-RAD50-NBS1 (MRN) complex detection occurs frequently in low-grade epithelial ovarian cancer

BACKGROUND

BRCA1/2-deficient ovarian carcinomas are recognized as target for Poly (ADP-ribose) polymerase (PARP) inhibitors. BRCA1 and BRCA2 proteins are involved in homologous recombination repair of double-strand DNA breaks. The relevance of other homologous recombination repair proteins, e.g. MRE11, RAD50, NBS1 (MRN complex) in ovarian carcinomas is unclear. The objective of this study was to investigate the prevalence of lack of MRE11, RAD50, NBS1 protein detection in epithelial ovarian cancer (EOC).

METHODS

A tissue microarray (TMA) with 134 EOC was immunohistochemically evaluated for MRE11, RAD50 and NBS1. Data was analysed for associations with clinicopathological parameters, histological subtype, patient overall survival and mismatch repair (MMR) protein status. Sensitivity towards the PARP inhibitor BMN673 was tested in two ovarian cancer cell lines (TOV-21 and OVTOKO) using colony formation assays.

RESULTS

Lack of MRN complex protein detection was seen in 41% (55/134) of EOC and was more frequent in low-grade (57.6%; 19/33) than in high-grade EOC (18.8%; 36/101; n = 134; p = 0.04). There was an association with the ovarian carcinoma subtype (60.3%; 35/58 lack of detection in type I versus 26.3%; 20/76 in type II; n = 134; p < 0.001) as well as undetectable DNA mismatch repair proteins MLH1 and MSH2 (89.3%; 25/28; n = 131; p < 0.001). MRE11 knockdown led to moderately increased sensitivity towards the PARP inhibitor BMN673 in one ovarian carcinoma cell line in vitro.

CONCLUSIONS

Frequent lack of MRE11, RAD50, NBS1 protein detection in type I human ovarian carcinomas is observed in EOC and our data suggests further investigation regarding sensitivity to PARP-inhibition in tumours lacking MRE11 expression.

Targeted next-generation sequencing enables reliable detection of HER2 (ERBB2) status in breast cancer and provides ancillary information of clinical relevance

HER2-positive breast cancers are a heterogeneous group of tumors, which share amplification and overexpression of HER2. In routine diagnostics, the HER2 (ERBB2) status is currently assessed by immunohistochemistry (IHC) and in situ hybridization (ISH). Data on targeted next-generation sequencing (NGS) approaches that could be used to determine the HER2 status are sparse. Employing two breast cancer-related gene panels, we performed targeted NGS of 41 FFPE breast cancers for which full pathological work-up including ISH and IHC results was available. Selected cases were analyzed by qPCR. Of the 41 cases, the HER2 status of the 4 HER2-positive and 6 HER2-negative tumors was independently detected by our NGS approach achieving a concordance rate of 100%. The remaining 31 cases were equivocal HER2 cases by IHC of which 5 showed amplification of HER2 by ISH. Our NGS approach classified all non-amplified cases correctly as HER2 negative and corroborated all but one of the 5 cases with amplified HER2 as detected by ISH. For the overall cohort, concordance between the gold standard and NGS was 97.6% (sensitivity 88.9% and specificity 100%). Additionally, we observed mutations in PIK3CA (44%), HER2 (8%), and CDH1 (6%) among others. Amplifications were found in CCND1 (12%), followed by MYC (10%) and EGFR (2%) and deletions in CDKN2A (10%), MAP2K4 and PIK3R1 (2% each). We here show that targeted NGS data can be used to interrogate the HER2 status with high specificity and high concordance with gold standard methods. Moreover, this approach identifies additional genetic events that may be clinically exploitable. © 2016 Wiley Periodicals, Inc.

Image-based computational quantification and visualization of genetic alterations and tumour heterogeneity

Recent large-scale genome analyses of human tissue samples have uncovered a high degree of genetic alterations and tumour heterogeneity in most tumour entities, independent of morphological phenotypes and histopathological characteristics. Assessment of genetic copy-number variation (CNV) and tumour heterogeneity by fluorescence in situ hybridization (ISH) provides additional tissue morphology at single-cell resolution, but it is labour intensive with limited throughput and high inter-observer variability. We present an integrative method combining bright-field dual-colour chromogenic and silver ISH assays with an image-based computational workflow (ISHProfiler), for accurate detection of molecular signals, high-throughput evaluation of CNV, expressive visualization of multi-level heterogeneity (cellular, inter- and intra-tumour heterogeneity), and objective quantification of heterogeneous genetic deletions (PTEN) and amplifications (19q12, HER2) in diverse human tumours (prostate, endometrial, ovarian and gastric), using various tissue sizes and different scanners, with unprecedented throughput and reproducibility.

Prognostic significance of POLE proofreading mutations in endometrial cancer

BACKGROUND

Current risk stratification in endometrial cancer (EC) results in frequent over- and underuse of adjuvant therapy, and may be improved by novel biomarkers. We examined whether POLE proofreading mutations, recently reported in about 7% of ECs, predict prognosis.

METHODS

We performed targeted POLE sequencing in ECs from the PORTEC-1 and -2 trials (n = 788), and analyzed clinical outcome according to POLE status. We combined these results with those from three additional series (n = 628) by meta-analysis to generate multivariable-adjusted, pooled hazard ratios (HRs) for recurrence-free survival (RFS) and cancer-specific survival (CSS) of POLE-mutant ECs. All statistical tests were two-sided.

RESULTS

POLE mutations were detected in 48 of 788 (6.1%) ECs from PORTEC-1 and-2 and were associated with high tumor grade (P < .001). Women with POLE-mutant ECs had fewer recurrences (6.2% vs 14.1%) and EC deaths (2.3% vs 9.7%), though, in the total PORTEC cohort, differences in RFS and CSS were not statistically significant (multivariable-adjusted HR = 0.43, 95% CI = 0.13 to 1.37, P = .15; HR = 0.19, 95% CI = 0.03 to 1.44, P = .11 respectively). However, of 109 grade 3 tumors, 0 of 15 POLE-mutant ECs recurred, compared with 29 of 94 (30.9%) POLE wild-type cancers; reflected in statistically significantly greater RFS (multivariable-adjusted HR = 0.11, 95% CI = 0.001 to 0.84, P = .03). In the additional series, there were no EC-related events in any of 33 POLE-mutant ECs, resulting in a multivariable-adjusted, pooled HR of 0.33 for RFS (95% CI = 0.12 to 0.91, P = .03) and 0.26 for CSS (95% CI = 0.06 to 1.08, P = .06).

CONCLUSION

POLE proofreading mutations predict favorable EC prognosis, independently of other clinicopathological variables, with the greatest effect seen in high-grade tumors. This novel biomarker may help to reduce overtreatment in EC.

Characterization of the 19q12 amplification including CCNE1 and URI in different epithelial ovarian cancer subtypes

BACKGROUND

CCNE1 is frequently amplified in high grade serous ovarian cancer and may serve as a target for ovarian cancer treatment. URI is closely related to CCNE1 at the 19q12 amplicon and may also contribute to the oncogenic effect. Our objective was to investigate the relevance of CCNE1 and URI gene amplification and protein expression in different histological subtypes of epithelial ovarian cancer (EOC).

METHODS

A novel dual-color 19q12 in situ hybridization (ISH), covering CCNE1 and URI, and chromosome 19 as a surrogate using Ventana BenchMark XT platform was developed and applied to 148 EOCs. URI and CCNE1 amplifications were separately assessed by fluorescence in situ hybridization (FISH). Immunohistochemistry using a Cyclin E1 and a novel URI monoclonal antibody was performed.

RESULTS

Amplification of 19q12 was found in 36.6%, CCNE1 in 21.7%, URI in 9.9%, and both genes simultaneously in 9% of EOC cases. High Cyclin E1 and URI protein expression were observed in 52.2% and 26.1%, respectively. Amplification of 19q12 occurred in all EOC subtypes and was associated with amplification and expression of CCNE1/Cyclin E1, URI, TP53 mutation, and advanced stage.

CONCLUSION

The novel 19q12 ISH probe reliably detects both CCNE1 and URI amplifications as confirmed by FISH. The combination of 19q12 amplification with Cyclin E1 and URI protein expression may help to select patients more likely to benefit from CDK2 targeted therapies.

KPNA2 is overexpressed in human and mouse endometrial cancers and promotes cellular proliferation

Endometrial cancer is the most frequently occurring malignancy of the female genital tract in Western countries. Although in many cases surgically curable, about 30% of the tumours represent an aggressive and untreatable disease. In an attempt to establish a reliable prognostic marker for endometrial carcinomas disregarding their histological diversity, we investigated the expression of KPNA2, a mediator of nucleocytoplasmic transport, and other cell proliferation-associated proteins and their correlation with cancer progression. We analysed patient tissue microarrays (TMAs) assembled from 527 endometrial cancer tissue specimens and uterus samples from a Trp53 knockout mouse model of endometrial cancer. Our data show that KPNA2 expression was significantly up-regulated in human endometrial carcinomas and associated with higher tumour grade (p = 0.026), higher FIGO stage (p = 0.027), p53 overexpression (p < 0.001), activation of the PI3K/AKT pathway, and epithelial-mesenchymal transition. Increased nuclear KPNA2 immunoreactivity was identified as a novel predictor of overall survival, independent of well-established prognostic factors in Cox regression analyses (hazard ratio 1.7, 95% CI 1.13-2.56, p = 0.01). No significant association between KPNA2 expression and endometrial cancer subtype was detected. In the mouse model, KPNA2 showed increased expression levels from precancerous (EmgD, EIC) to far-advanced invasive lesions. We further investigated the cell proliferation capacity after siRNA-mediated KPNA2 knockdown in the human endometrial cancer cell line MFE-296. KPNA2 silencing led to decreased proliferation of the cancer cells, suggesting interplay of the protein with the cell cycle. Taken together, increased expression of KPNA2 is an independent prognostic marker for poor survival. The mechanism of enhanced nucleocytoplasmic transport by KPNA2 overexpression seems a common event in aggressive cancers since we have shown a significant correlation of KPNA2 expression and tumour aggressiveness in a large variety of other solid tumour entities. Introducing KPNA2 immunohistochemistry in routine diagnostics may allow for the identification of patients who need more aggressive treatment regimens.

Effect of MRE11 loss on PARP-inhibitor sensitivity in endometrial cancer in vitro

AIM OF THE STUDY

To evaluate the frequency of MRE11/RAD50/NBS1 (MRN)-complex loss of protein expression in endometrial cancers (EC) and to determine whether loss of MRE11 renders the cancer cells sensitive to Poly(ADP-ribose) polymerase (PARP)-inhibitory treatment.

METHODS

MRN expression was examined in 521 samples of endometrial carcinomas and in 10 cancer cell lines. A putative mutation hotspot in the form of an intronic poly(T) allele in MRE11 was sequenced in selected cases (n = 26). Sensitivity to the PARP-inhibitor, BMN673 was tested in colony formation assays before and after MRE11 silencing using siRNA. Homologous recombination (HR) DNA repair was evaluated by RAD51-foci formation assay upon irradiation and drug treatment.

RESULTS

Loss of MRE11 protein was found in 30.7% of EC tumours and significantly associated with loss of RAD50, NBS1 and mismatch repair protein expression. One endometrial cell line showed a markedly reduced MRE11 expression due to a homozygous poly(T) mutation of MRE11, thereby exhibiting an increased sensitivity to BMN673. MRE11 depletion sensitizes MRE11 expressing EC cell lines to the treatment with BMN673. The increased sensitivity to PARP-inhibition correlates with reduced RAD51 foci formation upon ionizing radiation in MRE11-depleted cells.

CONCLUSION

Loss of the MRE11 protein predicts sensitivity to PARP-inhibitor sensitivity in vitro, defining it as an additional synthetic lethal gene with PARP. The high incidence of MRE11 loss in ECs can be potentially exploited for PARP-inhibitor therapy. Furthermore, MRE11 protein expression using immunohistochemistry could be investigated as a predictive biomarker for PARP-inhibitor treatment.

[Heterogeneity of epithelial ovarian carcinomas and their clinical significance]

Epithelial ovarian cancer is one of the most lethal gynecological malignant tumors despite improvement of the treatment. Recent molecular studies show that ovarian cancer is a heterogeneous disease which is reflected by different histologic types. These subtypes differ from their origin, pathogenesis and molecular alterations and can be divided in two major groups. The type I cancer (low grade) evolves from precursor lesions in a step-wise process. In contrast, the type II cancer (high grade) grows rapidly without any identifiable precursors. Among all subtypes is heterogeneity in the biological behavior which has implications in patient prognosis and treatment especially for individualized therapies in the future.

The G protein-coupled estrogen receptor (GPER) is expressed in two different subcellular localizations reflecting distinct tumor properties in breast cancer

INTRODUCTION

The G protein-coupled estrogen receptor (GPER) is a novel estrogen receptor that mediates proliferative effects induced by estrogen but also by tamoxifen. The aim of our study was to analyze the frequency of GPER in a large collective of primary invasive breast carcinomas, with special emphasis on the subcellular expression and to evaluate the association with clinicopathological parameters and patient overall survival.

METHODS

The tissue microarrays from formalin-fixed, paraffin embedded samples of primary invasive breast carcinomas (n = 981) were analyzed for GPER expression using immunohistochemistry. Expression data were compared to the clinicopathological parameters and overall survival. GPER localization was also analyzed in two immortalized breast cancer cell lines T47D and MCF7 by confocal immunofluorescence microscopy.

RESULTS

A predominantly cytoplasmic GPER expression was found in 189 carcinomas (19.3%), whereas a predominantly nuclear expression was observed in 529 cases (53.9%). A simultaneous comparable positive expression of both patterns was found in 32 of 981 cases (3.2%), and negative staining was detected in 295 cases (30%). Confocal microscopy confirmed the occurrence of cytoplasmic and nuclear GPER expression in T47D and MCF7. Cytoplasmic GPER expression was significantly associated with non-ductal histologic subtypes, low tumor stage, better histologic differentiation, as well as Luminal A and B subtypes. In contrast, nuclear GPER expression was significantly associated with poorly differentiated carcinomas and the triple-negative subtype. In univariate analysis, cytoplasmic GPER expression was associated with better overall survival (p = 0.012).

CONCLUSION

Our data suggest that predominantly cytoplasmic and/or nuclear GPER expression are two distinct immunohistochemical patterns in breast carcinomas and may reflect different biological features, reason why these patterns should be clearly distinguished in histological evaluations. Prospective studies will be needed to assess whether the expression status of GPER in breast carcinomas should be routinely observed by clinicians, for instance, before implementing endocrine breast cancer treatment.

Assessment of HER2 status in breast cancer: overall positivity rate and accuracy by fluorescence in situ hybridization and immunohistochemistry in a single institution over 12 years: a quality control study

Background

The gold standard of HER2 status assessment in breast cancer is still debated. Immunohistochemistry (IHC) and in-situ technology as fluorescent-labeled methodology (FISH) can be influenced by pre-analytical factors, assay-conditions and interpretation of test results. We retrospectively conducted this quality control study and analyzed HER2 test results in breast cancer within the routine diagnostic service in a single institution over a period of 12 years. We addressed the question how stable and concordant IHC and FISH methods are and whether HER2 positivity rate has changed over this period.

Methods

Data of 7714 consecutive HER2-FISH-assays in a period of 12 years (2001–2012) on breast cancer biopsies and excision specimens were retrospectively analyzed. From 2001 to 2004, FISH tests were performed from all cases with IHC score 3+ and 2+ (and in some tumors with IHC score 1+ and 0). From 2005–2010, HER2 status was only determined by FISH. From 2011–2012, all breast carcinomas were analyzed by both IHC and FISH. Scoring and cut-off-definition were done according to time-current ASCO-CAP and FDA-guidelines.

Results

Between 2001–2004, IHC score 3+ was diagnosed in 22% of cases, 69% of these 3+ cases were amplified by FISH. 6% of IHC score 0/1+ cases were amplified by FISH. There was a mean amplification rate of 15.8% (range 13 -19%) using FISH only HER2-assays (2005–2010). Starting 2008, a slight drop in the amplification rate from 17% to 14% was noticed due to the modified ASCO-criteria in 2007. From 2011–2012, 12% of cases were 3+ by IHC, 84% of them were amplified by FISH. Less than 1% of IHC score 0/1+ cases were amplified by FISH. Concordance between FISH and IHC increased from 83% to 97%.

Conclusions

Our quality control study demonstrates that HER2 positivity rate remained stable by FISH-technology but showed a significant variation by IHC over the analyzed 12 years. Improvement in concordance rate was due to standardization of pre-analytical factors, scoring and interpretation.

ARID1A mutations and PI3K/AKT pathway alterations in endometriosis and endometriosis-associated ovarian carcinomas

Endometriosis is a common gynecological disease affecting 6%–10% of women of reproductive age and is characterized by the presence of endometrial-like tissue in localizations outside of the uterine cavity as, e.g., endometriotic ovarian cysts. Mainly, two epithelial ovarian carcinoma subtypes, the ovarian clear cell carcinomas (OCCC) and the endometrioid ovarian carcinomas (EnOC), have been molecularly and epidemiologically linked to endometriosis. Mutations in the gene encoding the AT-rich interacting domain containing protein 1A (ARID1A) have been found to occur in high frequency in OCCC and EnOC. The majority of these mutations lead to a loss of expression of the ARID1A protein, which is a subunit of the SWI/SNF chromatin remodeling complex and considered as a bona fide tumor suppressor. ARID1A mutations frequently co-occur with mutations, leading to an activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, such as mutations in PIK3CA encoding the catalytic subunit, p110α, of PI3K. In combination with recent functional observations, these findings strongly suggest cooperating mechanisms between the two pathways. The occurrence of ARID1A mutations and alterations in the PI3K/AKT pathway in endometriosis and endometriosis-associated ovarian carcinomas, as well as the possible functional and clinical implications are discussed in this review.

TP53 mutations are common in all subtypes of epithelial ovarian cancer and occur concomitantly with KRAS mutations in the mucinous type

AIMS

Epithelial ovarian cancer (EOC) can be classified into four major types (serous, endometrioid, clear cell, mucinous). The prevalence of driver gene mutations in the different subtypes is controversial. High-grade serous carcinomas show frequent TP53 mutations, whereas KRAS and BRAF mutations are less common. In non-serous EOC, the relevance of these gene mutations remains to be elucidated.

METHODS

We investigated 142 formalin-fixed, paraffin-embedded EOC, including serous (n=63), endometrioid (n=29), clear cell (n=25), mucinous (n=14), and others (n=11) for mutations in TP53 exons 5-8, KRAS exons 2 and 3, and BRAF exon 15 by pyro-sequencing using the GS Junior 454 platform. The mutational status was correlated with clinicopathological features and patient overall survival.

RESULTS

We identified mutations in the coding region of TP53 in 51.4% (73/142), and of KRAS in 9.9% (14/142) but not of BRAF. TP53 mutations occurred frequently not only in high-grade serous carcinomas (58.7%), but also in mucinous (57%) and clear cell EOC (52%). TP53 mutations were associated with high-grade carcinomas (p=0.014), advanced FIGO stage (p=0.001), intraoperative residual disease >1cm (p=0.004), as well as poor overall survival (p=0.002). KRAS mutations were mainly identified in mucinous EOC (57%) and were concomitantly with TP53 mutations in five mucinous carcinomas (36%).

CONCLUSIONS

TP53 gene driver mutations are a common feature of all advanced ovarian cancer subtypes, whereas BRAF mutations seem to be a rare event in EOC. KRAS mutations with synchronous TP53 mutations occur predominantly in low-grade mucinous carcinomas, suggesting a specific molecular background of this ovarian cancer type.

The expression of histone deacetylase 1, but not other class I histone deacetylases, is significantly increased in endometriosis

Class I histone deacetylases (HDACs-1-3) play an important role in steroid hormone-dependent gene expression and in modulating cell survival and proliferation. We analyzed their expression in a tissue microarray including 74 endometriosis samples and 30 normal endometrium controls. The mean HDAC-1 immunoreactivity score (IRS ± standard deviation) was 7.6 ± 2.5 in endometriosis and 5.3 ± 2.3 in normal endometrium (P < .001). In contrast, the IRSs of HDAC-2 and -3 were 11.7 ± 0.7 and 11.8 ± 1.1 in endometriosis and 11.6 ± 1.0 and 11.9 ± 0.4 in normal endometrium (P = .7 and P = .2), respectively. Significant correlations were found between HDAC-1 and estrogen (-alpha/-beta) and progesterone receptor expression. In conclusion, HDAC-1, but not HDAC-2/-3, was significantly increased in endometriosis and associated with steroid hormone receptor expression that may reflect interdependence. In context with the literature, specific inhibitors of HDAC-1 may have inhibitory activities similar to those of broad-spectrum HDAC inhibitors and may be clinically tolerated, which would increase their chance as an option in the treatment of endometriosis.

p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans

Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II subtypes. The mTORC1 signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, analyses of 521 human endometrial carcinomas identified frequent mTORC1 pathway activation in type I as well as type II endometrial carcinoma subtypes. mTORC1 pathway activation and p53 expression or mutation status each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the mTORC1 pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and mTORC1 pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours.

Loss of ARID1A/BAF250a-expression in endometriosis: a biomarker for risk of carcinogenic transformation?

Mutations of the tumor-suppressor gene ARID1A result in the loss of protein expression of the BRG-associated factor 250a (BAF250a), a large subunit of transcription-regulating Human SWI/SNF complexes, which have an important role in the control of cell proliferation and tumor suppression. ARID1A mutations are particularly frequent in endometriosis-associated ovarian clear cell and endometrioid carcinomas, and were recently described as a possible key mechanism and early step in the transformation of endometriosis into cancer. Here, we examined the immunohistochemical expression pattern of BAF250a in a tissue microarray including 74 endometriosis and 30 endometrium samples. Ovarian cancer samples (n=136) served as a control. Epithelial BAF250a expression was assessable in 90/104 (87%) and stromal BAF250a expression in 95/104 (91%) of the endometriosis, and endometrium cases due to lack of adequate tissue in some spots. Complete lack of BAF250a expression was observed in three endometriomas (n=3/20, 15%) and one deep-infiltrating endometriosis sample (n=1/22, 5%), but in none of the peritoneal endometriosis (n=0/16) and eutopic endometrium samples (n=0/30). A comparison of the mean immunoreactivity scores revealed a significantly lower expression rate of BAF250a in endometriomas compared with normal endometrium (P<0.0005), as well as peritoneal (P=0.003) and deep-infiltrating endometriosis (P=0.02). Our data demonstrates that a complete loss of BAF250a expression is observable in some endometriotic lesions, especially in endometriomas. In addition, we report that a partial loss of BAF250a expression is occurring in the form of cell clusters indicating a clonal loss of BAF250a expression in these cells. The loss of expression of the tumor-suppressor protein BAF250a in some endometriomas possibly indicates a risk of malignant transformation in these cases, which could be of importance in the determination of individual treatment strategies. However, its role and value as a prognostic parameter in endometriosis needs to be further studied.

Expression of the G protein-coupled estrogen receptor (GPER) in endometriosis: a tissue microarray study

BACKGROUND

The G protein-coupled estrogen receptor (GPER) is thought to be involved in non-genomic estrogen responses as well as processes such as cell proliferation and migration. In this study, we analyzed GPER expression patterns from endometriosis samples and normal endometrial tissue samples and compared these expression profiles to those of the classical sex hormone receptors.

METHODS

A tissue microarray, which included 74 samples from different types of endometriosis (27 ovarian, 19 peritoneal and 28 deep-infiltrating) and 30 samples from normal endometrial tissue, was used to compare the expression levels of the GPER, estrogen receptor (ER)-alpha, ER-beta and progesterone receptor (PR). The immunoreactive score (IRS) was calculated separately for epithelium and stroma as the product of the staining intensity and the percentage of positive cells. The expression levels of the hormonal receptors were dichotomized into low (IRS < 6) and high (IRS > = 6) expression groups.

RESULTS

The mean epithelial IRS (+/- standard deviation, range) of cytoplasmic GPER expression was 1.2 (+/- 1.7, 0-4) in normal endometrium and 5.1 (+/- 3.5, 0-12) in endometriosis (p < 0.001), of nuclear GPER 6.4 (+/- 2.6, 0-12) and 6.8 (+/- 2.9, 2-12; p = 0.71), of ER-alpha 10.6 (+/- 2.4, 3-12) and 9.8 (+/- 3.0, 2-12; p = 0.26), of ER-beta 2.4 (+/- 2.2; 0-8) and 5.6 (+/- 2.6; 0-10; p < 0.001), and of PR 11.5 (+/- 1.7; 3-12) and 8.1 (+/- 4.5; 0-12; p < 0.001), respectively. The mean stromal IRS of nuclear GPER expression was 7.7 (+/- 3.0; 2-12) in endometrium and 10.8 (+/- 1.7; 6-12) in endometriosis (p < 0.001), of ER-alpha 8.7 (+/- 3.1; 2-12) and 10.6 (+/- 2.4; 2-12; p = 0.001), of ER-beta 1.8 (+/- 2.0; 0-8) and 5.4 (+/- 2.5; 0-10; p < 0.001), and of PR 11.7 (+/- 0.9; 8-12) and 10.9 (+/- 2.0; 3-12; p = 0.044), respectively. Cytoplasmic GPER expression was not detectable in the stroma of endometrium and endometriosis. The observed frequency of high epithelial cytoplasmic GPER expression levels was 50% (n = 30/60) in the endometriosis and none (0/30) in the normal endometrium samples (p < 0.001). High epithelial cytoplasmic GPER expression levels were more frequent in endometriomas (14/20, 70%; p = 0.01), as compared to peritoneal (9/18, 50%) or deep-infiltrating endometriotic lesions (7/22, 31.8%). The frequency of high stromal nuclear GPER expression levels was 100% (n = 74/74) in endometriosis and 76.7% (n = 23/30) in normal endometrium (p < 0.001). The frequency of high epithelial nuclear GPER expression levels did not differ between endometriosis and normal endometrium.

CONCLUSIONS

The present data indicate a unique GPER expression pattern in endometriosis, especially in endometriomas as compared to the normal endometrium. The overexpression of GPER in endometriotic lesions suggests a potential role for GPER in the hormonal regulation of endometriosis, which should be taken into consideration for future hormonal treatment strategies.

Abstract 3087: CD24 regulates tumor cell behaviour in a c-Src dependent fashion

CD24 is a glycosyl phosphatidylinositol (GPI)-anchored membrane protein that is frequently over-expressed in a variety of human carcinomas and is correlated with poor prognosis. In cancer cell lines, changes of CD24 expression can alter several cellular properties like invasion, proliferation and adhesion in vitro and tumor growth in vivo. However, little is known about the mechanisms by which CD24 mediates these effects. Here we have analyzed functional consequences of CD24 knock-down or over-expression in human cancer cell lines of different tumor entities (ovarian, lung, glioma). We show that presence or absence of CD24 was crucial to regulate the amount and activity of c-Src in lipid rafts. CD24-mediated effects on tyrosine-phosphorylated c-Src had impact on regulation of target genes affecting tumor cell invasion, proliferation and apoptosis. Invasive potential of tumor cells was controlled by the expression of the tissue factor pathway inhibitor-2 (TFPI-2), a potent inhibitor of extracellular matrix degradation that can block tumor cell invasion and metastasis. Silencing of CD24 or c-Src enhanced TFPI-2 expression and diminished invasion of SKOV3ip and A549 cells into matrigelTM. Conversely, over-expression of CD24 reduced TFPI-2 expression and enhanced invasion. Furthermore, an inverse correlation between expression of CD24 and TFPI-2 was observed by immunohistochemical analysis of primary breast cancers (N = 1174). TFPI-2 expression was highest in CD24 negative samples and lowered with increasing CD24 expression. Patients with a CD24 low/TFPI-2 high phenotype showed significantly better survival compared to CD24 high/TFPI-2 low patients (p=0.001). Additionally, STAT3 expression and phosphorylation were reduced by CD24 silencing. Diminished STAT3 activity was confirmed by specific reporter assays. Src depletion abrogated levels of p-STAT3 (Y705). In line with that, expression of classical STAT3 target genes like MCL-1, Cyclin D1 and Survivin was reduced after CD24 knock-down. Suppressed cell proliferation and enhanced apoptosis were observed in CD24 knock-down cells, suggesting a pivotal role of regulated target genes. An antibody to CD24 was effective in reducing tumor growth of lung- and pancreatic cancer xenografts in mice. Antibody treatment affected the level of Src-activity in the tumor and altered expression of STAT3 target genes. Our results provide evidence that CD24 regulates TFPI-2 and STAT3 activity via the c-Src non receptor tyrosin kinase. Targeting of CD24 by antibodies could represent a novel strategy for anti tumor therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3087. doi:1538-7445.AM2012-3087

Abstract 3293: p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans

Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II carcinoma subtypes. The PI3K-Akt-mTOR signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, immunohistochemical analyses of 521 human endometrial carcinomas identified frequent mTOR pathway activation in type I as well as type II endometrial carcinoma subtypes and mTOR pathway activation and p53 expression each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the PI3K-mTOR pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and PI3K-mTOR pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3293. doi:1538-7445.AM2012-3293

An intracellular targeted antibody detects EGFR as an independent prognostic factor in ovarian carcinomas

BACKGROUND

In ovarian cancer, the reported rate of EGFR expression varies between 4-70% depending on assessment method and data on patient outcome are conflicting.

METHODS

In this study we investigated EGFR expression and its prognostic value in a cohort of 121 invasive ovarian carcinomas, using a novel antibody against the intracellular domain of the receptor. We further evaluated an association between EGFR, the nuclear transporter CRM1 as well as COX-2. Furthermore, we evaluated EGFR expression in ten ovarian cancer cell lines and incubated cancer cells with Leptomycin B, a CRM1 specific inhibitor.

RESULTS

We observed a membranous and cytoplasmic EGFR expression in 36.4% and 64% of ovarian carcinomas, respectively. Membranous EGFR was an independent prognostic factor for poor overall survival in ovarian cancer patients (HR 2.7, CI 1.1-6.4, p = 0.02) which was also found in the serous subtype (HR 4.6, CI 1.6-13.4, p = 0.004). We further observed a significant association of EGFR with COX-2 and nuclear CRM1 expression (chi-square test for trends, p = 0.006 and p = 0.013, respectively). In addition, combined membranous EGFR/COX-2 expression was significantly related to unfavorable overall survival (HR 7.2, CI 2.3-22.1, p = 0.001).In cell culture, we observed a suppression of EGFR protein levels after exposure to Leptomycin B in OVCAR-3 and SKOV-3 cells.

CONCLUSIONS

Our results suggest that the EGFR/COX-2/CRM1 interaction might be involved in progression of ovarian cancer and patient prognosis. Hence, it is an interesting anti-cancer target for a combination therapy. Further studies will also be needed to investigate whether EGFR is also predictive for benefit from EGFR targeted therapies.

De novo expression of EphA2 in osteosarcoma modulates activation of the mitogenic signalling pathway

AIMS

In osteosarcoma patients the development of metastases, often to the lungs, is the most frequent cause of death. The aim of this study was to elucidate the molecular mechanisms governing osteosarcoma development and dissemination and, thereby, to identify possible novel drug targets for improved treatment.

METHODS AND RESULTS

Osteosarcoma samples were characterized using genome-wide microarrays: increased expression of the EphA2 receptor and its ligand EFNA1 was detected. In addition, increased expression of EFNB1, EFNB3 and EphA3 was suggested. Immunohistochemistry revealed an absence of EphA2 in normal bone, and de novo expression in osteosarcomas. EFNA1 was expressed in normal bone, but was significantly elevated in tumours. Further in vitro investigations on the functional role of EphA2 and EFNA1 showed that EFNA1 ligand binding induced increased tyrosine phosphorylation, receptor degradation and downstream mitogen-activated protein kinase (MAPK) activation. Interference with the MAPK pathway unravelled a potential autoregulatory loop governing mainly EFNA1 expression via the same pathway.

CONCLUSION

Upregulation and de novo expression of ephrins in osteosarcomas are involved in oncogenic signalling and thus might stimulate osteosarcoma metastasis.