Identification of functional and diverse circulating cancer-associated fibroblasts in metastatic castration-naïve prostate cancer patients

In prostate cancer (PCa), cancer-associated fibroblasts (CAFs) promote tumor progression, drug resistance, and metastasis. Although circulating tumor cells are studied as prognostic and diagnostic markers, little is known about other circulating cells and their association with PCa metastasis. Here, we explored the presence of circulating CAFs (cCAFs) in metastatic castration-naïve prostate cancer (mCNPC) patients. cCAFs were stained with fibroblast activation protein (FAP), epithelial cell adhesion molecule (EpCAM), and receptor-type tyrosine-protein phosphatase C (CD45), then FAP+EpCAM- cCAFs were enumerated and sorted using fluorescence-activated cell sorting. FAP+EpCAM- cCAFs ranged from 60 to 776 (389 mean ± 229 SD) per 2 × 108 mononuclear cells, whereas, in healthy donors, FAP+ EpCAM- cCAFs ranged from 0 to 71 (28 mean ± 22 SD). The mCNPC-derived cCAFs showed positivity for vimentin and intracellular collagen-I. They were viable and functional after sorting, as confirmed by single-cell collagen-I secretion after 48 h of culturing. Two cCAF subpopulations, FAP+CD45- and FAP+CD45+, were identified, both expressing collagen-I and vimentin, but with distinctly different morphologies. Collectively, this study demonstrates the presence of functional and viable circulating CAFs in mCNPC patients, suggesting the role of these cells in prostate cancer.

Vibrational signatures of dynamic excess proton storage between primary amine and carboxylic acid groups

Ammonium and carboxylic moieties play a central role in proton-mediated processes of molecular recognition, charge transfer or chemical change in (bio)materials. Whereas both chemical groups constitute acid-base pairs in organic salt-bridge structures, they may as well host excess protons in acidic environments. The binding of excess protons often precedes proton transfer reactions and it is therefore of fundamental interest, though challenging from a quantum chemical perspective. As a benchmark for this process, we investigate proton storage in the amphoteric compound 5-aminovaleric acid (AV), within an intramolecular proton bond shared by its primary amine and carboxylic acid terminal groups. Infrared ion spectroscopy is combined with ab initio Molecular Dynamics (AIMD) calculations to expose and rationalize the spectral signatures of protonated AV and its deuterated isotopologues. The dynamic character of the proton bond confers a fluxional structure to the molecular framework, leading to wide-ranging bands in the vibrational spectrum. These features are reproduced with remarkable accuracy by AIMD computations, which serves to lay out microscopic insights into the excess proton binding scenario.

Circulating tumour cells are associated with histopathological growth patterns of colorectal cancer liver metastases

Histopathological Growth Patterns (HGPs) have prognostic and predictive value in patients with Colorectal Liver Metastases (CRLM). This study examined whether preoperative measurement of Circulating Tumour Cells (CTCs) is associated with HGP. CTCs were prospectively enumerated in 7.5 ml of blood using the FDA-approved CellSearch system in patients who underwent local treatment of CRLM with curative intent between 2008 and 2021. All CTC samples were collected on the day of local treatment. Patients treated with neoadjuvant chemotherapy for CRLM or with extrahepatic disease at the time of CTC sampling were excluded. HGP was scored retrospectively following the current consensus guidelines. The association between CTCs and HGP was investigated through multivariable logistic regression. Data were available for 177 patients, desmoplastic HGP (dHGP) was observed in 34 patients (19%). There were no statistically significant differences in patient and tumour characteristics between dHGP and non-dHGP at baseline. Patients with dHGP had longer overall - and disease-free survival (logrank p = 0.003 and 0.003, respectively) compared to patients with non-dHGP. CTCs were not detected in 25(74%) of dHGP patients and in 68(48%) of non-dHGP patients (chi-squared p = 0.006). Preoperative absence of CTCs was the only significant predictor for dHGP in multivariable logistic regression (Odds Ratio 2.7, 95%CI 1.1-6.8, p = 0.028), Table 3. Preoperative absence of CTCs is associated with dHGP in chemo naive CRLM patients without extrahepatic disease. Based on our results, CTC count alone is not sufficient to preoperatively identify HGPs, but integration of CTC count in multivariable prediction models may aid the preoperative identification of HGPs of CRLM.

Structural Determination of Lysine-Linked Cisplatin Complexes via IRMPD Action Spectroscopy: NNs and NO- Binding Modes of Lysine to Platinum Coexist

Despite its success as an anticancer drug, cisplatin suffers from resistance and produces side effects. To overcome these limitations, amino-acid-linked cisplatin analogues have been investigated. Lysine-linked cisplatin, Lysplatin, (Lys)PtCl₂, exhibited outstanding reactivity toward DNA and RNA that differs from that of cisplatin. To gain insight into its differing reactivity, the structure of Lysplatin is examined here using infrared multiple photon dissociation (IRMPD) action spectroscopy. To probe the influence of the local chemical environment on structure, the deprotonated and sodium-cationized Lysplatin complexes are examined. Electronic structure calculations are performed to explore possible modes of binding of Lys to Pt, their relative stabilities, and to predict their infrared spectra. Comparisons of the measured IRMPD and predicted IR spectra elucidate the structures contributing to the experimental spectra. Coexistence of two modes of binding of Lys to Pt is found where Lys binds via the backbone and side-chain amino nitrogen atoms, NN_s, or to the backbone amino and carboxylate oxygen atoms, NO^-. Glycine-linked cisplatin and arginine-linked cisplatin complexes have previously been found to bind only via the NO^- binding mode. Present results suggest that the NN_s binding conformers may be key to the outstanding reactivity of Lysplatin toward DNA and RNA.

Standardizing resolution definition in scanning helium microscopy

Resolution is a key parameter for microscopy, but methods for standardizing its definition are often poorly defined. For a developing technique such as scanning helium microscopy, it is critical that a consensus-based protocol for determining instrument resolution is prepared as a written standard to allow both comparable quantitative measurements of surface topography and direct comparisons between different instruments. In this paper we assess a range of quantitative methods for determining instrument resolution and determine their relative merits when applied to the specific case of the scanning helium microscope (SHeM). Consequently, we present a preliminary protocol for measuring the resolution in scanning helium microscopy based upon utilizing appropriate test samples with sets of slits of well-defined dimensions to establish the quantitative resolution of any similar instrument.

Disease activity in inflammatory bowel disease patients is associated with increased liver fat content and liver fibrosis during follow-up

PURPOSE

Liver steatosis is a frequently reported condition in patients with inflammatory bowel disease (IBD). Different factors, both metabolic and IBD-associated, are believed to contribute to the pathogenesis. The aim of our study was to calculate the prevalence of liver steatosis and fibrosis in IBD patients and to evaluate which factors influence changes in steatosis and fibrosis during follow-up.

METHODS

From June 2017 to February 2018, demographic and biochemical data was collected at baseline and after 6-12 months. Measured by transient elastography (FibroScan), liver steatosis was defined as Controlled Attenuation Parameter (CAP) ≥248 and fibrosis as liver stiffness value (Emed) ≥7.3 kPa. IBD disease activity was defined as C-reactive protein (CRP) ≥10 mg/l and/or fecal calprotectin (FCP) ≥150 μg/g. Univariate and multivariate regression analysis was performed; a p-value of ≤0.05 was considered significant.

RESULTS

Eighty-two out of 112 patients were seen for follow-up; 56% were male. The mean age was 43 ± 16.0 years, and mean BMI was 25.1 ± 4.7 kg/m². The prevalence of liver steatosis was 40% and of fibrosis was 20%. At baseline, 26 patients (32%) had an active episode of IBD. Using a multivariate analysis, disease activity at baseline was associated with an increase in liver steatosis (B = 37, 95% CI 4.31-69.35, p = 0.027) and liver fibrosis (B = 1.2, 95% CI 0.27-2.14, p = 0.016) during follow-up.

CONCLUSIONS

This study confirms the relatively high prevalence of liver steatosis and fibrosis in IBD patients. We demonstrate that active IBD at baseline is associated with both an increase in liver steatosis and fibrosis during follow-up.

Structural determination of arginine-linked cisplatin complexes via IRMPD action spectroscopy: arginine binds to platinum via NO- binding mode

Cisplatin, (NH₃)₂PtCl₂, has been known as a successful metal-based anticancer drug for more than half a century. Its analogue, Argplatin, arginine-linked cisplatin, (Arg)PtCl₂, is being investigated because it exhibits reactivity towards DNA and RNA that differs from that of cisplatin. In order to understand the basis for its altered reactivity, the deprotonated and sodium cationized forms of Argplatin, [(Arg-H)PtCl₂]^- and [(Arg)PtCl₂ + Na]⁺, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy in the IR fingerprint and hydrogen-stretching regions. Complementary electronic structure calculations are performed using density functional theory approaches to characterize the stable structures of these complexes and to predict their infrared spectra. Comparison of the theoretical IR spectra predicted for various stable conformations of these Argplatin complexes to their measured IRMPD spectra enables determination of the binding mode(s) of Arg to the Pt metal center to be identified. Arginine is found to bind to Pt in a bidentate fashion to the backbone amino nitrogen and carboxylate oxygen atoms in both the [(Arg-H)PtCl₂]^- and [(Arg)PtCl₂ + Na]⁺ complexes, the NO^- binding mode. The neutral side chain of Arg also interacts with the Pt center to achieve additional stabilization in the [(Arg-H)PtCl₂]^- complex. In contrast, Na⁺ binds to both chlorido ligands in the [(Arg)PtCl₂ + Na]⁺ complex and the protonated side chain of Arg is stabilized via hydrogen-bonding interactions with the carboxylate moiety. These findings are consistent with condensed-phase results, indicating that the NO^- binding mode of arginine to Pt is preserved in the electrospray ionization process even under variable pH and ionic strength.

Evaluation of multiple transcriptomic gene risk signatures in male breast cancer

Male breast cancer (BCa) is a rare disease accounting for less than 1% of all breast cancers and 1% of all cancers in males. The clinical management is largely extrapolated from female BCa. Several multigene assays are increasingly used to guide clinical treatment decisions in female BCa, however, there are limited data on the utility of these tests in male BCa. Here we present the gene expression results of 381 M0, ER+ve, HER2-ve male BCa patients enrolled in the Part 1 (retrospective analysis) of the International Male Breast Cancer Program. Using a custom NanoString™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDX®, and MammaPrint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by us previously. We also examined the prognostic value of other risk scores such as the Genomic Grade Index (GGI), IHC4-mRNA and our prognostic 95-gene signature. In this sample set of male BCa, we demonstrated prognostic utility on univariate analysis. Across all signatures, patients whose samples were identified as low-risk experienced better outcomes than intermediate-risk, with those classed as high risk experiencing the poorest outcomes. As seen with female BCa, the concordance between tests was poor, with C-index values ranging from 40.3% to 78.2% and Kappa values ranging from 0.17 to 0.58. To our knowledge, this is the largest study of male breast cancers assayed to generate risk scores of the current commercial and academic risk tests demonstrating comparable clinical utility to female BCa.

Characteristics and Outcomes of COVID-19 in Patients on Left Ventricular Assist Device Support

Supplemental Digital Content is available in the text.

Background:

The coronavirus disease 2019 (COVID-19) pandemic continues to afflict millions of people worldwide. Patients with end-stage heart failure and left ventricular assist devices (LVADs) may be at risk for severe COVID-19 given a high prevalence of complex comorbidities and functional impaired immunity. The objective of this study is to describe the clinical characteristics and outcomes of COVID-19 in patients with end-stage heart failure and durable LVADs.

Methods:

The Trans-CoV-VAD registry is a multi-center registry of LVAD and cardiac transplant patients in the United States with confirmed COVID-19. Patient characteristics, exposure history, presentation, laboratory data, course, and clinical outcomes were collected by participating institutions and reviewed by a central data repository. This report represents the participation of the first 9 centers to report LVAD data into the registry.

Results:

A total of 40 patients were included in this cohort. The median age was 56 years (interquartile range, 46–68), 14 (35%) were women, and 21 (52%) were Black. Among the most common presenting symptoms were cough (41%), fever, and fatigue (both 38%). A total of 18% were asymptomatic at diagnosis. Only 43% of the patients reported either subjective or measured fever during the entire course of illness. Over half (60%) required hospitalization, and 8 patients (20%) died, often after lengthy hospitalizations.

Conclusions:

We present the largest case series of LVAD patients with COVID-19 to date. Understanding these characteristics is essential in an effort to improve the outcome of this complex patient population.

Abstract PS19-08: Intratumoral heterogeneity of second-harmonic generation scattering from tumor collagen and its effects on metastatic risk prediction

Second harmonic generation (SHG) is an intrinsic optical signal that can be generated from fibrillar collagen. The directionality of SHG emission is influenced by the diameter and spacing of collagen fibrils, and the disorder in their packing within collagen fibers. One measure of SHG directionality is the ratio of forward- to backward-scattered SHG, or “F/B”. F/B has been used to assess healthy vs diseased tissue in breast, ovarian, and lung cancer, and is an independent prognostic indicator of metastasis free survival time in ER+, lymph node-negative (N0), invasive ductal carcinoma (IDC). Here we assess the heterogeneity in F/B within tumor sections from ER+ N0 IDC, and its effect on the use of F/B for metastatic risk prediction. We find that F/B of tumor collagen varies between the tumor/host interface and the more cellular tumor bulk (p<0.0001, Student’s t-test), and that F/B from the tumor/host interface, but not tumor bulk, is prognostic of metastasis free survival in 95 IDC ER+ N0 patients (p=0.0020 and 0.10, respectively, log rank test for trend). This result was repeated with two additional image analysis procedures to generate F/B with reduced user input and hence reduced possibility of bias. Using Random Survival Forests to generate a data-driven predictive model, we find that F/B from the tumor/host interface, but not bulk, as well as a 21-gene prognostic score inferred from Affymetrix data, both contribute to predicting metastasis-free survival in this cohort. Any tool to help predict metastasis and assist with treatment decisions is likely to be applied in combination with the now well-established genomic scores. To understand how F/B can support genomic methods for guiding treatment decisions we divided our patient samples into two cohorts based upon the value of their 21-gene score relative to the TAILORx cutoff of 26 (separating low-intermediate and high-risk groups). The F/B value from tumor-host interface identifies a subgroup of patients in the low-intermediate risk group with poor clinical outcome (p=0.045, log rank test for trend). Overall, this data reveals that intratumor heterogeneity can impact the ability of F/B to predict patient outcome, and that F/B specifically from the tumor-host interface may provide a tool to better identify patients in need of adjuvant treatment or enrollment in clinical trials.

Citation Format: Edward Brown, Danielle Desa, Wencheng Wu, Robert Hill, John Martens, Robert Strawderman, Bradley Turner. Intratumoral heterogeneity of second-harmonic generation scattering from tumor collagen and its effects on metastatic risk prediction [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 PS19-08.

Task Adaptations as a Function of Content Knowledge: A Functional Analysis

Purpose: The purpose of the study was to investigate how teachers' pedagogical content knowledge (PCK) in the form of task adaptations differed as a function of content knowledge. Method: Participants were three elementary school teachers (two females and one male) and their students (n = 66). Functional analysis of instructional events (i.e., adaptations) between teachers and students was used to examine PCK before and after a content knowledge workshop in crawl swimming. The appropriateness of the adaptations was measured and all data were collected through live observation by trained observers. Results: All teachers increased their average number of task adaptations per lesson after the content knowledge workshop. Appropriateness of adaptations increased substantially for two teachers but decreased for one teacher. Discussion/Conclusion: Functional analysis of student-teacher interactions is a valuable tool to examine teachers' PCK. The interrelationship between student- and teacher behavior can be modified through a content knowledge workshop.

Long-term milrinone therapy as a bridge to heart transplantation: Safety, efficacy, and predictors of failure

BACKGROUND

Studies of long-term inotrope use in advanced HF have previously provided limited and conflicting results. This study aimed to evaluate the safety and efficacy of long-term milrinone use and identify predictors of failure to bridge to orthotropic heart transplant (OHT) in a cohort of end-stage heart failure (HF) patients listed for heart transplantation and receiving inotrope therapy.

METHODS

The study included 150 adults listed for OHT at a single center from 2001 to 2017 who received milrinone therapy for ≥30 days. Multivariate Cox proportional hazards models were used to identify factors associated with "failure" (left ventricular assist device, intra-aortic balloon pump, status downgrade due to instability, death) vs. "success" (OHT, recovery) during bridging to OHT.

RESULTS

"Failure" occurred in 33 (22%) patients. Factors independently associated with failure included male sex (HR = 7.6; p = 0.004), no implantable cardioverter-defibrillator (HR = 3.8; p = 0.009), and lack of guideline-directed medical therapy (GDMT) with a beta-blocker (HR = 7.8; p = 0.002) or angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (HR = 6.3; p < 0.001). Patients who received fewer guideline-directed medications had a higher cumulative probability of failure. Adverse events included central line-associated bloodstream infection (2.55 per 1000 line-days) and arrhythmia (1.59 per 1000 treatment-days).

CONCLUSIONS

Our findings suggest that long-term milrinone therapy in selected patients is associated with a high rate of successful bridging to OHT and a low rate of adverse events. Patients intolerant of GDMT are more likely to fail to bridge to OHT without mechanical support. Sex differences in outcomes associated with milrinone therapy should be explored.

Abstract P4-10-03: The genomic landscape of male breast cancers using the oncomine comprehensive assay for actionable mutations

Introduction: Male breast cancer (BCa) is a rare disease accounting for less than 1% of all breast cancers (BC) and 1% of all cancers in males. The clinical management is largely extrapolated from female BCa. Few studies have examined the genomic landscape of male BCas, with six male BCas included in The Cancer Genome Atlas (TCGA). Familial studies of male BCas have shown genomic changes similar to female BCa, while a larger targeted sequencing study of 59 male breast cancers identified recurrent mutations affecting PIK3CA and GATA3. To date, there is still limited information regarding the genomic landscape of male BCas; particularly in the context of identifying targeted treatments. To reveal genomic changes that characterize male BCas in the context of known cancer driver genes linked to prognosis and targeted agents, we performed a targeted sequencing study on 248 male BCas from the International Male Breast Cancer Program. Methods: 248 primary M0, ER+ve, HER2-ve male BCas enrolled in the Part 1 (retrospective joint analysis) International Male Breast Cancer Program of 1483 patients diagnosed between 1990-2010 (Cardoso et al. Annals of Oncology, 2018) were processed for nucleic acid extraction from formalin-fixed paraffin embedded (FFPE) tissues. Using the Thermo Fisher Scientific Oncomine Comprehensive Assay v3 (OCAv3), a validated targeted sequencing panel currently used in the NCI-MATCH trial (NCT02465060), we evaluated mutational and copy number variations (CNVs) of genes that are prognostic or predictive to targeted therapies currently in use in the clinic or late-stage clinical trials. The OCAv3 DNA pan-cancer panel assays 115 genes for determining mutational status (48 full coding and 67 hotspot) as well as copy-number assessment in 43 genes. The OCAv3 uses Ampliseq-based technology linked to the Oncomine NGS workflow to identify actionable mutations and CNVs Results: Of the 248 samples assayed, 216 passed strict quality control parameters (87.1%). Using the Oncomine NGS workflow, actionable mutations at ≥5% variant allele frequency (VAF) were most frequently identified in PIK3CA (29.2%), BRCA2 (11.1%), NF1 (11.6%), indels in TP53 (10.6%), ATR (5.6%), ATRX (5.1%), indel BRCA2 (5.1%), TP53 point mutations (4.6%), MET (4.6%), ATM (4.6%), NOTCH2 (4.6%), CHEK1 (4.2%), FANCI (4.2%), PTEN (3.2%) with a number of additional genes identified at lower frequencies. Gene amplifications were most frequently detected in MYC (24.5%), FGFR1 (14.8%), CCND1 (12%), FGF3 (9.7%), FGF19 (9.7%), MDM2 (6.5%), CDK4 (1.4%), FGFR3, MDM4, ERBB2 (0.9% each), and FLT3, AR, MYCL, CDK6, IGF1R, FGFR4, KRAS, AKT3 and ESR1 (0.5% each). Although the results here describe the mutations and copy-number changes deemed to be actionable, further analysis of all non-actionable somatic mutations and CNVs will be presented and compared to female BCas previously assayed using the same panel. Conclusion: In this targeted sequencing study of the largest series of male BCas to our knowledge, we have revealed that PIK3CA continues to be a frequently altered gene in both male and female BCas. However, there is an enrichment of mutations in genes related to DNA repair in male BCs. Interestingly, while MYC is commonly amplified in female BCa, a higher frequency of amplified cases were seen in male BCas, in contrast to female BCas. Together with our previously generated transcriptional profiling data in this data set, we believe that both common and unique biological processes comprising male and female BCas will ultimately improve their clinical management and move towards the goal of precision medicine.

This work has been funded by the Breast Cancer Research Foundation (BCRF).

Citation Format: Jane Bayani, Coralie Poncet, Cheryl Crozier, Quang M Trinh, Megan Hopkins, Aime Lambert Uwimana, Tammy Piper, Carrie Cunningham, Monika Sobol, Stefan Aebi, Kim Benstead, Oliver Bogler, Lissandra Dal Lago, Florentine Hilbers, Ingrid Hedenfalk, Larissa Korde, Barbro Linderholm, John Martens, Lavinia Middleton, Melissa Murray, Catherine Kelly, Cecilia Nilsson, Monika Nowaczyk, Stephanie Peeters, Aleksandra Peric, Peggy Porter, Carolien Schröder, Isabel T Rubio, Kathryn J Ruddy, Christi van Asperen, Danielle Van Den Weyngaert, Carolien HM van Deurzen, Elise van Leeuwen-Stok, Joanna Vermeij, Eric Winer, Lincoln D Stein, Sharon H Giordano, Fatima Cardoso, John MS Bartlett. The genomic landscape of male breast cancers using the oncomine comprehensive assay for actionable mutations [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 P4-10-03.

The molecular genetic make-up of male breast cancer

Male breast cancer (MBC) is extremely rare and accounts for less than 1% of all breast malignancies. Therefore, clinical management of MBC is currently guided by research on the disease in females. In this study, DNA obtained from 45 formalin-fixed paraffin-embedded (FFPE) MBCs with and 90 MBCs (52 FFPE and 38 fresh-frozen) without matched normal tissues was subjected to massively parallel sequencing targeting all exons of 1943 cancer-related genes. The landscape of mutations and copy number alterations was compared to that of publicly available estrogen receptor (ER)-positive female breast cancers (smFBCs) and correlated to prognosis. From the 135 MBCs, 90% showed ductal histology, 96% were ER-positive, 66% were progesterone receptor (PR)-positive, and 2% HER2-positive, resulting in 50, 46 and 4% luminal A-like, luminal B-like and basal-like cases, respectively. Five patients had Klinefelter syndrome (4%) and 11% of patients harbored pathogenic BRCA2 germline mutations. The genomic landscape of MBC to some extent recapitulated that of smFBC, with recurrent PIK3CA (36%) and GATA3 (15%) somatic mutations, and with 40% of the most frequently amplified genes overlapping between both sexes. TP53 (3%) somatic mutations were significantly less frequent in MBC compared to smFBC, whereas somatic mutations in genes regulating chromatin function and homologous recombination deficiency-related signatures were more prevalent. MDM2 amplifications were frequent (13%), correlated with protein overexpression (P = 0.001) and predicted poor outcome (P = 0.007). In conclusion, despite similarities in the genomic landscape between MBC and smFBC, MBC is a molecularly unique and heterogeneous disease requiring its own clinical trials and treatment guidelines.

Associations between AR-V7 status in circulating tumour cells, circulating tumour cell count and survival in men with metastatic castration-resistant prostate cancer

BACKGROUND

The interpretation of the presence of AR-V7 in circulating tumour cells (CTCs) in men with metastatic castration-resistant prostate cancer (mCRPC) remains to be elucidated. AR-V7 may hold promise as a predictive biomarker, but there may be prognostic impact of AR-V7 positivity as well. To investigate the clinical value of AR-V7, we determined whether AR-V7 detection in CTCs in patients with mCRPC is associated with CTC counts and survival.

METHODS

Between December 2011 and January 2019, three prospective clinical trials collected clinical data of patients with mCRPC, who progressed after docetaxel and/or enzalutamide or abiraterone. Baseline (and follow-up) blood samples were withdrawn determining CTC count and AR-V7 expression. The majority of patients started cabazitaxel as the next line of treatment after AR-V7 characterisation.

RESULTS

A total of 127 samples were evaluable for the analysis of CTC count versus AR-V7 status. Although an association was observed between AR-V7 and CTC count in all patients with mCRPC (p = 0.017), no such association was found in the prognostic unfavourable subgroup of patients with ≥5 CTCs. After adjusting for clinical prognostic factors, AR-V7 expression in CTCs was not associated with overall survival (hazard ratio = 1.33, 95% confidence interval = 0.81-2.15, p = 0.25).

CONCLUSION

We found that AR-V7 expression in CTCs had no additional prognostic value in patients with mCRPC, mostly treated with cabazitaxel. In patients with mCRPC with a predefined worse prognosis of a higher CTC count (≥5), a predictive biomarker is an important unmet medical need. Prospective trials should investigate whether AR-V7 detection in CTCs may guide treatment selection for these adverse prognosis patients.

Characterization of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABCG International Male Breast Cancer Program

Background

Male breast cancer (BC) is rare, managed by extrapolation from female BC. The International Male BC Program aims to better characterize and manage this disease. We report the results of part I, a retrospective joint analysis of cases diagnosed during a 20-year period.

Methods

Patients with follow-up and tumor samples, treated between 1990 and 2010, in 93 centers/9 countries. Samples were centrally analyzed in three laboratories (the United Kingdom, the Netherlands and the United States).

Results

Of 1822 patients enrolled, 1483 were analyzed; 63.5% were diagnosed between 2001 and 2010, 57 (5.1%) had metastatic disease (M1). Median age at diagnosis: 68.4 years. Of 1054 M0 cases, 56.2% were node-negative (N0) and 48.5% had T1 tumors; 4% had breast conserving surgery (BCS), 18% sentinel lymph-node biopsy; half received adjuvant radiotherapy; 29.8% (neo)adjuvant chemotherapy and 76.8% adjuvant endocrine therapy (ET), mostly tamoxifen (88.4%). Per central pathology, for M0 tumors: 84.8% ductal invasive carcinomas, 51.5% grade 2; 99.3% estrogen receptor (ER)-positive; 81.9% progesterone receptor (PR)-positive; 96.9% androgen receptor (AR)-positive [ER, PR or AR Allred score ≥3]; 61.1% Ki67 expression low (<14% positive cells); using immunohistochemistry (IHC) surrogates, 41.9% were Luminal-A-like, 48.6% Luminal-B-like/HER-2-negative, 8.7% HER-2-positive, 0.3% triple negative. Median follow-up: 8.2 years (0.0-23.8) for all, 7.2 years (0.0-23.2), for M0, 2.6 years (0.0-12.7) for M1 patients. A significant improvement over time was observed in age-corrected BC mortality. BC-specific-mortality was higher for men younger than 50 years. Better overall (OS) and recurrence-free survival (RFS) were observed for highly ER+ (P = 0.001), highly PR+ (P = 0.002), highly AR+ disease (P = 0.019). There was no association between OS/RFS and HER-2 status, Ki67, IHC subtypes nor grade.

Conclusions

Male BC is usually ER, PR and AR-positive, Luminal B-like/HER2-negative. Of note, 56% patients had T1 tumors but only 4% had BCS. ER was highly positive in >90% of cases but only 77% received adjuvant ET. ER, PR and AR were associated with OS and RFS, whereas grade, Ki67 and IHC surrogates were not. Significant improvement in survival over time was observed.

Abstract P6-19-01: Evaluation of multiple transcriptomic gene risk signatures in male breast cancer

Introduction: Male breast cancer (MBC) is a rare disease accounting for less than 1% of all breast cancers (BC) and 1% of all cancers in males. The clinical management is largely extrapolated from female BC. Several multigene assays are increasingly used to guide clinical treatment decisions in female BC, however there is little data on the utility of these tests in MBC.

Methods: Here we present the gene expression results of 380 M0, ER+ve, HER2-ve MBCs enrolled in the Part 1 (retrospective joint analysis) International Male Breast Cancer Program of 1483 patients diagnosed between 1990-2010 (Cardoso et al. Annals of Oncology, 2018). Using a custom Nanostring™ panel comprised of the genes from the commercial risk tests Prosigna®, OncotypeDx® and Mammaprint®, risk scores and intrinsic subtyping data were generated to recapitulate the commercial tests as described by Bayani and Yao et al (npjBreast Cancer, 2017). Survival outcomes by risk classification were analyzed using Cox models with time-dependent covariates when the proportional hazard assumption was not met and adjusted for clinical and treatment variables.

Results: Prosigna-like risk scores identified 99 (26.1%) as low-risk, 159 (41.8%) as intermediate-risk, and 122 (32.1%) as high-risk. Using the TAILORx cut-off (25) for OncotypeDx-like risk of recurrence scoring, 158 (41.6%) were identified as low-risk, while 222 (58.4%) were identified as high-risk. MammaPrint-like results identified 175 (46.1%) as low-risk and 205 (53.9%) as high-risk. Overall, patients classified as high-risk had higher grade, more nodal involvement, larger tumors, and more frequently treated with chemotherapy than low-risk patients. Survival analyses demonstrated clear clinical utility for each test, showing patients at high-risk with poor relapse-free survival (RFS) as compared to patients classified as low-risk: Prosigna-like RFS at 3-years (HR=2.20, 95% CI, 1.28-3.80); Oncotype-like RFS at 3-years (HR=1.92, 95% CI, 1.17-3.17); MammaPrint-like RFS (HR=1.51, 95% CI, 1.00-2.27); with similar findings for distant relapse-free survival (DRFS) and overall survival (OS). Across outcomes and all gene signatures, patients with concordant Low/Low risk classification had better prognosis than those with concordant High/High risk classification. PAM50 intrinsic subtyping identified 147 (38.7%) as Luminal A, 57 (15.0%) as Luminal B, 80 (21.1%) as Her2-enriched and 96 (25.3%) as Basal-like; showing overall 34.5% concordance to clinic-pathological subtyping by central pathology (95% CI, 29.7%-39.5%). Comparison between the tests in the MBC cohort and a comparable cohort of female BC from the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial processed in the same way will be presented.

Conclusion: Common transcriptomic assays designed to assess residual risk, validated in female BC, provide similar information in male BC patients. Not surprisingly, disagreement between test results at the individual patient level was observed. To our knowledge, this is the largest study of MBC assayed to generate risk scores of the current commercial BC tests to demonstrate their clinical utility and their differences and similarity to female BC.

This work has been funded by the Breast Cancer Research Foundation (BCRF).

Citation Format: Bayani J, Poncet C, Yao CQ, Crozier C, Anouk N, Piper T, Cunningham C, Sobol M, Aebi S, Benstead K, Bogler O, Dal Lago L, Fraser J, Hilbers FH, Hedenfalk I, Korde L, Linderholm B, Martens J, Middleton L, Murray M, Kelly C, Nilsson C, Nowaczyk M, Peeters S, Peric A, Porter P, Schröder C, Rubio IT, Ruddy KJ, van Asperen C, Van Den Weyngaert D, van Deurzen C, van Leeuwen-Stok E, Vermeij J, Winer E, Boutros PC, Giordano SH, Cardoso F, Bartlett JM. Evaluation of multiple transcriptomic gene risk signatures in male breast cancer [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 P6-19-01.

Abstract 1527: Splicing factors determine breast cancer cell mitosis through control of sister chromatid cohesion

Breast cancer is the mostly diagnosed cancer in women worldwide and is also the leading cause of death from cancer in women, mainly due to metastasis formation. Accumulating evidence suggests that RNA splicing is critical in breast cancer progression. To investigate the role of every single component of the splicing machinery (the spliceosome) in this process, we systematically evaluated the effect of siRNA-mediated knockdown of 244 splicing factors on proliferation in two highly proliferative breast cancer cell lines MDA-MB-231 and Hs578T. Hits of the primary screen were validated with single siRNAs and separated based on their effects on migration and proliferation respectively. Knockdown of nine validated proliferation hits, amongst which was SF3B1, a known breast cancer driver gene, resulted for all nine hits in a distinct poly-lobed nuclear phenotype in both cell types, accompanied by increased DNA content and higher number of cells in G1-S transition. Increased levels of phospho-Histone H3 and lack of metaphase alignment suggested a defect in mitosis, which was confirmed by decreased RNA expression of sister chromatid cohesion factors MAU2, ESPL1 and SMC1A and interestingly, increased CDCA5 RNA levels. Upon splicing factor knockdown, CDCA5 intron 1 was retained resulting in decreased CDCA5 protein levels, inaccurate metaphase alignment and finally cell death. To identify the direct partners of the splicing factors that control mitosis, we coupled pull-down of GFP fused splicing factors with mass spectrometry. Seven out of the nine splicing factors that were identified in our screen causing poly-lobed nuclear phenotypes, resided in the same protein complex together with proteins involved in snRNP assembly and some mitosis-related factors. In conclusion, we have identified several splicing factors that are critically determining breast cancer cell proliferation through modulating the expression of chromatid cohesion factors and thereby mediating the successful metaphase alignment and ultimate mitosis.

Citation Format: Esmee Koedoot, John Martens, Sylvia E. Le Dévédec, Bob van de Water. Splicing factors determine breast cancer cell mitosis through control of sister chromatid cohesion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1527.

Low temperature approach for high density electrical feedthroughs for neural implants using maskless fabrication techniques

Implantable electronic packages for neural implants utilize reliable electrical feedthroughs that connect the inside of a sealed capsule to the components that are exposed to the surrounding body tissue. With the ongoing miniaturization of implants requiring ever higher integration densities of such feedthroughs new technologies have to be investigated. The presented work investigates the sealing of vertical feedthroughs in aluminum-oxide-substrates with gold stud-bumps. The technology enables integration densities of up to 1600/cm ² while delivering suitable water leak rates for realistic implantation durations of miniaturized packages (feedthrough-count $>50$, package-volume $<2$ cm $^{3})$ of more than 50 years. All manufacturing steps require temperatures below $420 ^{\circ}\mathrm {C}$ and are suitable for maskless rapid prototyping.

Abstract 5179: Uncovering the signaling landscape controlling breast cancer cell migration identifies splicing PRPF4B as a metastasis driver

Metastasis is the major cause of death in cancer patients and migration of cancer cells from the primary tumor to distant sites is the prerequisite of metastasis formation. Here we applied an imaging-based RNAi phenotypic cell migration screen uing two highly migratory basal breast cancer cell lines (Hs578T and MDA-MB-231 to provide a repository of candidate metastasis drug targets. We screened ~4,200 individual target genes covering most cell signaling components. We discovered 133 and 113 migratory modulators of Hs578T and MDA-MB-231, respectively, of which 45 genes were common denominators of cell migration. Interaction networks of candidate migratory modulators were in common with networks of different clinical breast cancer prognostic and metastasis classifiers. The splicing factors PRPF4B and BUD31 and the transcription factor BPTF were amplified in human primary breast tumors and the expression was associated with metastasis-free survival. Depletion of PRPF4B, BUD31 and BPTF caused primarily downregulation of genes involved in focal adhesion and ECM-interaction pathways. PRPF4B was essential for TNBC cell migration and critical for breast cancer metastasis formation in vivo, making PRPF4B a candidate for further drug development. Our systematic phenotypic screen provides an important repository for signaling determinants that functionally drive cancer cell migration.

Citation Format: Bob van de Water, Erik Danen, Esmee Koedoot, Maria Rogkoti, Michiel Fokkelman, Sylvia Le Devedec, John Martens, Peter Stoilov, John Foekens. Uncovering the signaling landscape controlling breast cancer cell migration identifies splicing PRPF4B as a metastasis driver [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5179.

Abstract 4978: On circular RNAs in breast cancer

Introduction Circular RNA was already discovered many decades ago and circRNAs were long considered idiosyncrasies of the splicing machinery processing precursor mRNA to mature mRNA. A much more recent take on this phenomenon showed an unanticipated abundance of circRNA isoforms in human cells. In breast cancer some work has already been done on publicly available TCGA data, but this analysis has a big limitation since the RNA-seq data were prepared using a poly(A) selection step, thereby missing most circRNAs (which lack a poly(A) tail). Here we describe the identification of circRNAs in a large cohort of 348 primary breast tumors, using RNA-seq data obtained without using a poly(A) selection step in the generation of the sequence libraries. We developed a method that, in contrast to previous identification methods, does not rely on unmapped reads or known splice-junctions.

Methods RNA-seq data were generated, using total RNA and removing ribosomal RNA using Ribo Zero (Illumina, USA). Paired-end (75 bases) sequencing was performed on an Illumina HiSeq 2000. The resulting fastq files were mapped to GRCh38 using STAR (version 2.4.2a) and the resulting bam files were sorted and indexed. CircRNAs were identified directly on the bam file generated by STAR; assuming a circular RNA molecule is present, the sequence read that aligns over the crossing of the non-canonical junction would, on a linear reference, get two different mapped locations. The read-mate aligns somewhere in between these two locations with the head of the read-mate pointing toward the head of the junction read, as would be expected in a properly paired read. Finding additional read-pairs showing this configuration, but always with a breakpoint at the exact same location, strengthens the evidence for circular transcripts.

Results In our cohort of 348 primary breast cancer cases we identified 25,783 circRNAs having a junction over exons of a gene. Of these, 13,853 (54%) were identified in at least 2 samples, and 426 circRNAs were found in at least 150 samples. The top recurrent circRNA was CDR1, a known circRNA that functions as a miR-7 sponge. Other previously described circRNAs were also present in our list. Of the circRNAs with sufficient data, 668 (41%) showed a poor (R&lt;0.2) and 210 (13%) showed a negative correlation with the expression level of the linear gene. We validated several circRNAs by PCR and sequencing, including CNOT2 and CREBBP, the former showing prognostic value, the latter a known breast cancer driver gene. Additional analyses are ongoing and will be presented at the annual meeting.

Conclusion circRNAs are an abundant RNA species in breast cancer, several of which may just be a remnant of the splicing machinery. However, several circRNAs have characteristics of being regulated and thus may have a functional role in breast cancer. Due to their structural stability, candidate circRNAs may serve as good biomarkers for diagnosis and therapy-monitoring in liquid biopsies.

Citation Format: Marcel Smid, Vanja de Weerd, Saskia Wilting, Anieta Sieuwerts, Serena Nik-Zainal, John Martens. On circular RNAs in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4978.

A Multimodal Skin Cancer Prevention Program for Heart Transplant Patients

Background:

Immunosuppressant medications are essential for long-term survival following transplantation but increase the risk of developing skin cancer. Prevention and early detection of skin cancer requires screening and sun protection behaviors that can be achieved with patient education.

Problem Statement:

Our method for educating post heart transplant patients regarding skin cancer was inconsistent and was not effective. The aim of this project was to develop and integrate a multimodal skin cancer education program to increase knowledge and protective behaviors for heart transplant recipients.

Methods:

Twenty-five post heart transplant patients who were scheduled to be seen for routine posttransplant care at a single-center transplant center between October 26, 2016, and November 15, 2016, took part in a multimodal skin cancer education program.

Results:

There was a significant increase in knowledge between pretest and posttest 1 ( P <.01) and pretest and posttest 2 ( P <.01). A significant increase in sun protective behavior was noted. The project noted that knowledge and behavior was retained, knowledge score posttest 1 to posttest 2 ( P = .085), all had seen a dermatologist or had an appointment scheduled, and self skin exam retention was noted between posttest 1 and posttest 2 ( P = .25).

Process Addressed:

The feasibility of and findings from this intervention have led the clinic team to implement this protocol as part of the standard care for all patients.

Conclusions:

These data suggests that a multimodal intensive skin cancer education program may be effective at increasing knowledge and protective behavior with heart transplant recipients.

Image formation in the scanning helium microscope

The scanning helium microscope (SHeM) is a new addition to the array of available microscopies, particularly for delicate materials that may suffer damage under techniques utilising light or charged particles. As with all other microscopies, the specifics of image formation within the instrument are required to gain a full understanding of the produced micrographs. We present work detailing the basics of the subject for the SHeM, including the specific nature of the projection distortions that arise due to the scattering geometry. Extension of these concepts allowed for an iterative ray tracing Monte Carlo model replicating diffuse scattering from a sample surface to be constructed. Comparisons between experimental data and simulations yielded a minimum resolvable step height of (67 ± 5) µm and a minimum resolvable planar angle of (4.3 ± 0.3)° for the instrument in question.

Deamidation of Protonated Asparagine-Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study

Peptide deamidation of asparaginyl residues is a spontaneous post-translational modification that is believed to play a role in aging and several diseases. It is also a well-known small-molecule loss channel in the MS/MS spectra of protonated peptides. Here we investigate the deamidation reaction, as well as other decomposition pathways, of the protonated dipeptide asparagine-valine ([AsnVal + H]+) upon low-energy activation in a mass spectrometer. Using a combination of infrared ion spectroscopy, guided ion beam tandem mass spectrometry, and theoretical calculations, we have been able to identify product ion structures and determine the energetics and mechanisms for decomposition. Deamidation proceeds via ammonia loss from the asparagine side chain, initiated by a nucleophilic attack of the peptide bond oxygen on the γ-carbon of the Asn side chain. This leads to the formation of a furanone ring containing product ion characterized by a threshold energy of 129 ± 5 kJ/mol (15 kJ/mol higher in energy than dehydration of [AsnVal + H]+, the lowest energy dissociation channel available to the system). Competing formation of a succinimide ring containing product, as has been observed for protonated asparagine-glycine ([AsnGly + H]+) and asparagine-alanine ([AsnAla + H]+), was not observed here. Quantum-chemical modeling of the reaction pathways confirms these subtle differences in dissociation behavior. Measured reaction thresholds are in agreement with predicted theoretical reaction energies computed at several levels of theory.

Abstract P5-23-01: Clinical and biological characterization of male breast cancer (BC) EORTC 10085/TBCRC 029/BOOG 2013-02/BIG 2-07: Baseline results from the prospective registry

BACKGROUND: Through the International Male Breast Cancer Program, a prospective registry for male BC was created with the goals of evaluating 1) the clinical and biological features of this disease and 2) assessing feasibility of a prospective therapeutic clinical trial.

METHODS: All men, with any stage histologically proven invasive breast cancer, age 3 18 years, and newly presenting at the participating institutions (within 3 months prior) were eligible. Patients were enrolled for 30 months after activation of the first center, through February 2017. Per the study design, if &lt;100 men enrolled, the study would be considered a failure and therapeutic trials would not be pursued through this network. Epidemiologic data, staging, pathologic features, and BRCA status were collected. Treatment and outcome data collection is ongoing. Optional collection of FFPE tumor samples, blood, and QOL were performed in the US, the Netherlands, and Latin America. Clinical database lock for this report was May 30, 2017. We currently report patient and disease characteristics and will update with patterns of treatment for the presentation. Outcomes and biological samples will be analyzed in the future.

RESULTS: 557 patients were enrolled: 75% in Europe, 20% in United States, 5% in other countries. 6.3% of patients had missing forms. Median age was 67 years (range 26-92). 93% were diagnosed 2010-2017. Among patients with complete data, 79% presented with a breast mass. 88% were M0 and 12% M1. Among M0 patients: 47%, 39%, 2%, and 11% had T1, T2, T3, and T4 disease respectively; 52% were N0. Overall, 98% had ER+ disease and 11% had HER2+ cancer. 14% had grade 1, 56% had grade 2, and 30% had grade 3 tumors. Among 112 men who underwent BRCA1 testing, 1 was positive. Among 118 men who had BRCA2 testing, 18 (15%) were positive. 21% of men had prior or concurrent malignancies, with the following most common sites: prostate, non-melanoma skin, colorectal, and melanoma. The prevalence of previously identified possible risk factors for male breast cancer were: overweight/obesity (72%), former/current smoker (51%), current alcohol 31 drink daily (41%), family history of breast cancer (35%), gynecomastia (16%), history radiation exposure (8%), use of anti-androgens (1%), and use of estrogens (1%).

CONCLUSION: Through an international collaborative effort, we were able to prospectively accrue 557 patients to a male breast cancer registry. These results demonstrate feasibility of pursuing a therapeutic clinical trial in men with breast cancer. In addition, this study shows the relatively low uptake of BRCA testing, high rates of concurrent/prior malignancy, and the rates of potentially modifiable risk factors in this patient population.

Funding from Breast Cancer Research Foundation, Susan G. Komen, Dutch Pink Ribbon Foundation, Swedish Breast Cancer Association (BRO) and EBCC Council.

Citation Format: Giordano SH, Schröder CP, Poncet C, van Leeuwen-Stok E, Linderholm B, Abreu MH, Rubio I, Van Poznak C, Morganstern D, Cameron D, Vleugel MM, Smilde TJ, Bozovic-Spasojevic I, Korde L, Russell NS, den Hoed IDM, Honkoop AH, van der Velden AWG, van 't Riet M, Dijkstra N, Bogler O, Goulioti T, Hilsenbeck S, Ruddy KJ, Wolff A, van Deurzen CHM, Martens J, Bartlett JMS, Aalders K, Tryfonidis K, Cardoso F. Clinical and biological characterization of male breast cancer (BC) EORTC 10085/TBCRC 029/BOOG 2013-02/BIG 2-07: Baseline results from the prospective registry [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-23-01.

Differential Effects of Fibroblast Growth Factors on Expression of Genes of the Plasminogen Activator and Insulin-like Growth Factor Systems by Human Breast Fibroblasts

In breast stroma urokinase plasminogen activator (uPA) is predominantly expressed by fibroblasts located in the near vicinity of tumor cells, and fibroblast-derived insulin-like growth factor-1 (IGF-1) may be involved in inhibiting the expression of uPA in these fibroblasts. To investigate a possible role for fibroblast growth factors (FGFs), we evaluated the expression of components of the PA system and the IGF system in normal and tumor-tissue-derived human breast fibroblasts exposed to various FGFs in vitro. mRNA analysis revealed that FGF-1, FGF-2 and FGF-4 induced the mRNA expression levels of uPA, tPA, uPAR, PAI-1 and PAI-2, and reduced those of IGF-1, IGF-1R, IGF-2R and IGFBP-4, without significantly affecting the levels of IGFBP-3, IGFBP-5 and IGFBP-6 mRNA. Concerning the expression of IGF-2 mRNA, the effects mediated by FGF-1, FGF-2 and FGF-4 were divergent. In general, the effects elicited by FGF-1 on the various mRNA levels studied were rapid and short-term. Those mediated by FGF-2 overall lagged behind but were longer-lasting. For FGF-4 an in between pattern was observed. Blocking transcription and translation demonstrated that a) both the FGF-1 and FGF-2 induced effects were the result of altered gene transcription or mRNA stability, b) the short-term effects mediated by FGF-1 and FGF-2 required de novo protein synthesis, and c) the long-term effects elicited by FGF-2 did not depend on de novo protein synthesis during the first 24 h, but were triggered by proteins produced or made available thereafter. The data presented propose that of the FGFs studied (FGF-1, -2, -4, -5, and -7), FGF-2 is the most attractive target for therapeutical strategies aimed at diminishing the contribution of stromal fibroblasts in the PA-directed breast tumor proteolysis.

Aging of stromal-derived human breast fibroblasts might contribute to breast cancer progression

Age is an important factor in the development and spread of breast cancer. Stromal cells also contribute to breast cancer growth and metastasis through the production of extracellular matrix (ECM) modifiers such as urokinase type plasminogen activator (uPA), its receptor (uPAR), its inhibitors (PAI-1 and PAI-2), matrix metalloproteinases (MMPs), and growth factors, including the fibroblast and insulin-like growth factors (FGF’s and IGF’s). In the present study we have investigated whether breast fibroblasts aged in vitro through passage in culture display altered levels of the plasminogen activator system and growth factors that are known to modulate that system.

With real-time RT-PCR we found that during passage human breast fibroblasts, whether derived from the tumour burden or from matched adjacent normal breast tissue, exhibited a consistent increase in PAI-1 and FGF-1 and a decrease in MMP-2 mRNA expression. In addition, in 5 out of 7 fibroblast strains we observed an induction of uPA expression in combination with a reduced IGF-1 expression. Interestingly, while during aging MMP-2 protein increased in all tumour-derived fibroblast strains, these protein levels were reduced in all normal-tissue-derived fibroblasts. No other clear-cut age-dependent alterations were found in the all-together 25 factors investigated. We furthermore demonstrate in one tumour-derived fibroblast strain that the increases in uPA and PAI-1 mRNA and MMP-2 protein production are inversely related to the telomere length. Artificially increasing telomere length in this fibroblast strain by expressing human telomerase reverse transcriptase (hTERT) prevented senescence and resulted in late passage cultures with early passage uPA, PAI-1 and MMP-2 levels.

Our results show that aging accompanied by telomere loss induces PAI-1 and FGF-1 mRNA expression in all breast fibroblast strains, increases uPA and decreases IGF-1 mRNA expression in a subset, and increases MMP-2 protein expression only in tumour-derived breast fibroblasts. These age-induced levels of PAI-1, FGF-1, uPA and MMP-2 in stromal breast fibroblast could contribute to breast cancer progression.

The Predictive Value of PITX2 DNA Methylation for High-Risk Breast Cancer Therapy: Current Guidelines, Medical Needs, and Challenges

High-risk breast cancer comprises distinct tumor entities such as triple-negative breast cancer (TNBC) which is characterized by lack of estrogen (ER) and progesterone (PR) and the HER2 receptor and breast malignancies which have spread to more than three lymph nodes. For such patients, current (inter)national guidelines recommend anthracycline-based chemotherapy as the standard of care, but not all patients do equally benefit from such a chemotherapy. To further improve therapy decision-making, predictive biomarkers are of high, so far unmet, medical need. In this respect, predictive biomarkers would permit patient selection for a particular kind of chemotherapy and, by this, guide physicians to optimize the treatment plan for each patient individually. Besides DNA mutations, DNA methylation as a patient selection marker has received increasing clinical attention. For instance, significant evidence has accumulated that methylation of the PITX2 (paired-like homeodomain transcription factor 2) gene might serve as a novel predictive and prognostic biomarker, for a variety of cancer diseases. This review highlights the current understanding of treatment modalities of high-risk breast cancer patients with a focus on recommended treatment options, with special attention on the future clinical application of PITX2 as a predictive biomarker to personalize breast cancer management.

Abstract 103: Blockage of Cdc7/CDK9 signaling sensitizes triple negative breast cancer to EGFR-targeted therapy

The treatment of Triple-Negative Breast Cancer (TNBC) still represents a profound clinical challenge, the disease being disproportionately responsible for breast cancer-associated deaths. As a consequence, the identification of targeted agents, which synergize with current therapeutic options, is paramount. Resistance to EGFR-tyrosine kinase inhibitors (TKIs), despite frequent EGFR overexpression and reliance on downstream signalling pathways in TNBC, remains endemic. Recent data has also suggested that kinase-inhibition of EGFR in itself is insufficient, given the kinase-independent functions of the protein in transcriptional regulation and DNA-repair may permit prolonged EGFR-mediated signalling in the presence of inhibitors. We performed a kinase inhibitor drug screen (378 kinase inhibitors targeting ~40 different cancer-related kinases) to identify synergistic activity with EGFR inhibition in TNBC. We demonstrate that the dual cdc7/CDK9 inhibitor PHA-767491 synergizes with multiple EGFR-TKIs (Erlotinib, Gefitinib and Lapatinib) in vitro to overcome resistance to EGFR-targeted therapy in various TNBC cell lines. Combined inhibition of EGFR and cdc7/CDK9 resulted in reduced cell proliferation, accompanied by induction of apoptosis and G2-M cell cycle-arrest. Combination therapy inhibited crucial components of the DNA-replicative machinery and also proteins involved in CDK9-mediated transcriptional elongation. Moreover, higher expression of cdc7 and POLR2A was found to be significantly correlated with poorer survival rates in breast cancer patients. Additionally, this synergistic combination effectively inhibited the growth of cells isolated from patient-derived TNBC xenografts under ex vivo culture conditions, highlighting the utility of targeting common transcriptional nodes in cancers addicted to growth factor-mediated signalling pathways.

Citation Format: Ronan P. McLaughlin, Jichao He, Vera van der Noord, Jevin Redel, Marcel Smid, Lambert Dorssers, John Martens, John Foekens, Yinghui Zhang, Bob van de Water. Blockage of Cdc7/CDK9 signaling sensitizes triple negative breast cancer to EGFR-targeted therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 103. doi:10.1158/1538-7445.AM2017-103

Long-term follow-up and quality of life after robot assisted sacrohysteropexy

OBJECTIVE

The aim of this study is to investigate the effect of robot assisted laparoscopic sacrohysteropexy (RALS), with preservation of the uterus, in patients with pelvic organ prolapse on short and long term outcome. We report on (anatomical) status of the prolaps and the associated health related quality of life of women treated with RALS before and five years after surgery.

STUDY DESIGN

A prospective cohort study in a teaching hospital in The Netherlands was performed. Quality of life was assessed pre-operative, post-operative and five years after RALS using the UDI/IIQ validated self-questionnaire designed for Dutch-speaking patients. Clinical and operative data were prospectively collected up to five years. Statistical analysis of categorical data was performed with the paired T-test. Descriptive statistics were computed with the use of standard methods for means, median and proportions.

RESULTS

Hundred women with utero vaginal prolapse were treated with RALS with preservation of the uterus. The overall success rate of pelvic organ prolapse (POP) was 89.2%. After surgery the quality of life improved (P<0.05) Overall health status, based on a 0-100% visual analogue scale (VAS), improved from 72.6% pre-operative to 82.2% six weeks postoperative (P<0.05). Postoperative patients experienced less feelings of nervousness (P=0.01), shame (P<0.05) and frustration (P<0.05). The positive effects on these feelings remained present after five years. The learning curve shows a decrease in operating time with gained experience.

CONCLUSION

RALS has proven to be a safe and effective treatment for uterine preserving surgery in cases of pelvic organ prolapse. The long term anatomical outcomes and quality of life after RALS compare favorably with laparoscopic and open hysteropexy.

BRCA1-deficient breast cancer cell lines are resistant to MEK inhibitors and show distinct sensitivities to 6-thioguanine

Germ-line or somatic inactivation of BRCA1 is a defining feature for a portion of human breast cancers. Here we evaluated the anti-proliferative activity of 198 FDA-approved and experimental drugs against four BRCA1-mutant (HCC1937, MDA-MB-436, SUM1315MO2, and SUM149PT) and four BRCA1-wild-type (MDA-MB-231, SUM229PE, MCF10A, and MCF7) breast cancer cell lines. We found that all BRCA1-mutant cell lines were insensitive to inhibitors of mitogen-activated protein kinase kinase 1 and 2 (MEK1/2) Selumetinib and Pimasertib in contrast to BRCA1-wildtype control cell lines. However, unexpectedly, only two BRCA1-mutant cell lines, HCC1937 and MDA-MB-436, were hypersensitive to a nucleotide analogue 6-thioguanine (6-TG). SUM149PT cells readily formed radiation-induced RAD51-positive nuclear foci indicating a functional homologous recombination, which may explain their resistance to 6-TG. However, the reason underlying 6-TG resistance of SUM1315MO2 cells remains unclear. Our data reveal a remarkable heterogeneity among BRCA1-mutant cell lines and provide a reference for future studies.

A simple counter-flow cooling system for a supersonic free-jet beam source assembly

A simple design for an inexpensive, cooled, free-jet beam source is described. The source assembly features an integrated cooling system as supplied by a counter-flow of chilled nitrogen, and is composed primarily of off-the-shelf tube fittings. The design facilitates rapid implementation and eases subsequent alignment with respect to any downstream beamline aperture. The source assembly outlined cools the full length of the stagnation volume, offering temperature control down to 100 K and long-term temperature stability better than ±1 K.

Abstract S4-07: Tamoxifen resistance driven by the DNA cytosine deaminase APOBEC3B in recurrent estrogen receptor positive breast cancer

Recent studies have implicated the DNA cytosine deaminase APOBEC3B as a major source of mutation in breast cancer. APOBEC3B explains a large proportion of both dispersed and clustered cytosine mutations, the latter of which are also called kataegis. APOBEC3B expression levels correlate with poor outcomes for patients with estrogen receptor positive breast cancer. While targeted therapies, such as tamoxifen, are available to treat these tumors, secondary drug resistance often develops. Here we suppressed endogenous APOBEC3B in the estrogen receptor positive breast cell line MCF-7L with shRNA. Lowered levels of APOBEC3B did not affect in vitro growth or sensitivity to estradiol. In a xenograft model of tamoxifen therapy, suppression of APOBEC3B associated with prolonged responses to tamoxifen (p&lt;0.05). Furthermore, APOBEC3B over-expression did not affect in vitro cell growth but accelerated the development of tamoxifen-resistant tumors in vivo. In addition, we studied two separate cohorts of 285 breast cancer patients who received first line treatment with tamoxifen for recurrent disease. High APOBEC3B expression levels measured in the primary tumor associated significantly with unfavorable progression free survival in multivariate analysis that included the traditional predictive factors (age, dominant relapse site, disease-free interval, estrogen receptor and progesterone receptor, and adjuvant chemotherapy; HR=1.67, p=0.0001). The median period of progression free survival was 7.5 months for patients with APOBEC3B high primary tumors and 13.3 months for those with APOBEC3B low tumors (p&lt;0.0.0001). These studies demonstrate that APOBEC3B drives resistance to endocrine treatment with tamoxifen in recurrent disease.

Citation Format: Harris R, Law E, Sieuwerts A, LaPara K, Leonard B, Starrett G, Temiz NA, Sweep F, Span P, Foekens J, Martens J, Yee D. Tamoxifen resistance driven by the DNA cytosine deaminase APOBEC3B in recurrent estrogen receptor positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S4-07.

Hamilton's rule, inclusive fitness maximization, and the goal of individual behaviour in symmetric two-player games

Hamilton's original work on inclusive fitness theory assumed additivity of costs and benefits. Recently, it has been argued that an exact version of Hamilton's rule for the spread of a pro-social allele (rb > c) holds under nonadditive pay-offs, so long as the cost and benefit terms are defined as partial regression coefficients rather than pay-off parameters. This article examines whether one of the key components of Hamilton's original theory can be preserved when the rule is generalized to the nonadditive case in this way, namely that evolved organisms will behave as if trying to maximize their inclusive fitness in social encounters.