Couch, Fergus J.

Background: Carriers of a pathogenic variant (PV) in BRCA1 face a high risk of breast cancer. This study estimated the risk of developing breast cancer according to mutation type and location. Methods: BRCA1 carriers with no personal history of breast cancer or bilateral mastectomy were included. Detailed information on clinical and family history was collected by questionnaire. Survival analysis was used to estimate 15-year cumulative risk according to PV type and location. Results: A total of 3677 BRCA1 carriers were followed for a mean of 7.2 years (range 0.1–15.0 years); 481 incident breast cancers were documented. Overall, the 15-year cumulative incidence was 25%. Risk estimates varied by exon, ranging from 9% (exon 21) to 19% (exon 12) to 36% (exon 15); however, strata were small. Carriers of four founder mutations common in Eastern Europe (c.5263_5264insC, c.181T > G, c.66_67delAG and c.4034delA) experienced a lower-than-expected cancer risk (15.9–24.4%) compared to other PVs (28.8%) (p = 0.02). Conclusions: Although our data suggests some variability in penetrance based on specific BRCA1 PV, this was based on a large number of founder mutations. Breast cancer management strategies should continue to be based on comprehensive risk assessment.

Abstract PARP inhibitors (PARPis) are now a standard of care for high-grade serous ovarian cancer (HGSOC), but resistance to these drugs poses a significant concern, necessitating the exploration of novel treatment strategies. Here we investigated the mechanism underlying enhanced PARPi activity in HGSOC cells following treatment with brigatinib—a second-generation anaplastic lymphoma kinase (ALK) inhibitor approved for treating lung cancer. Our previous work has shown that brigatinib is a dual inhibitor of tyrosine kinases FAK and EPHA2 with subsequent additive reduction in downstream PI3K/AKT and MAPK/ERK cell survival signaling. Suppression of these pathways conferred PARPi sensitivity to HGSOC cell lines and patient-derived xenograft (PDX) models, particularly in those with high FAK and EPHA2. To dissect the mechanism linking the FAK/EPHA2 – AKT/ERK pathway to PARPi synergy, we focused on proteomics approaches which revealed that FRA1—an Activator Protein 1 (AP-1) transcription factor known to be downstream of AKT/ERK—and its targets were decreased by brigatinib treatment. In subsequent phosphoproteomics approaches and cell-based confirmatory studies, a phosphorylation crucial for FRA1 stability was found to be disrupted, leading to reduction in total FRA1 protein levels and synergy with PARPis. To explore how FRA1 mediates response to PARPis, immunoblotting analysis revealed that PARPis increased the abundance of FRA1 in HGSOC cells at early timepoints, indicating potential involvement in an adaptive survival response. Follow-up pharmacologic and gene silencing techniques demonstrated that brigatinib still reduces FRA1 in PARPi-treated cells, and FRA1 depletion induces apoptosis when combined with PARPi to levels comparable to brigatinib treatment. Overall, our studies unveil a beneficial ALK-independent effect of brigatinib that may offer new avenues for considering its repurposing as a HGSOC therapy through disruption of a PARPi-induced adaptive survival mechanism. Citation Format: Julie R. Duffield, Xiaonan Hou, Benjamin W. Wilson, Anjali Prasad, Iman K. McKeon-Makki, Amelia M. Huehls, Xinyan Wu, Cristina Correia, Melissa C. Larson, Fergus J. Couch, Ann L. Oberg, Scott H. Kaufmann, Larry M. Karnitz, Arun Kanakkanthara. A PARP-inhibitor-induced early adaptive survival response is tackled through depletion of FRA1 by brigatinib in high-grade serous ovarian carcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Ovarian Cancer Research; 2025 Sep 19-21; Denver, CO. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl):Abstract nr A024.

Abstract Background: Ovarian cancer is the sixth leading cause of cancer deaths among women in the United States. South Asians in the USA, including Asian Indians and Pakistani Americans (AIPA), are a rapidly growing yet under-researched group. This study aims to analyze the clinical features, survival rates, treatment, and outcomes of ovarian cancer among AIPA women in the United States. Methods: Adult women diagnosed with ovarian cancer between 2000 and 2023 within the Surveillance, Epidemiology, and End Results (SEER) registry were identified utilizing ICD codes. The analysis focused on comparing clinical characteristics and outcomes between AIPA and Non-Hispanic White (NHW)women and excluded all women of other races/ethnicities or unknown race/ethnicity. Baseline characteristics, including age at diagnosis, disease stage, and treatment, were compared between AIPA and NHW women utilizing a chi-squared test for categorical variables and a t-test for continuous variables. The 5-year overall survival (OS) was estimated for each race/ethnicity by the Kaplan-Meier method, and the OS was further compared between AIPA and NHW in a cox-proportional hazard regression analysis adjusting for age at diagnosis, grade, histology, TNM stage, surgical debulking, completeness of debulking surgery, and receipt of chemotherapy. Similar comparisons of baseline characteristics and OS were also performed in the subset of women with high-grade serous ovarian cancer (HGSOC). Result: A total of 86, 485 women met the inclusion criteria, of which 1, 179 were AIPA and 85, 306 were NHW. AIPA had a significantly younger median age at diagnosis compared to NHW women in the overall population (57 vs. 65 years, p<0.001) and among 448 AIPA and 29, 677 NHW women with HGSOC (58 vs. 65 years, p<0.001). Approximately two-thirds of women in both groups presented with Stage III or IV ovarian cancer at diagnosis and had a serous subtype of ovarian cancer. Similarly, after the exclusion of unknown grade, high-grade tumors accounted for more than two-thirds (75 vs. 72%) of the ovarian cancer cases in both groups. AIPA were more likely to undergo debulking surgery (85 vs. 80%, p<0.001) and receive chemotherapy (77 vs. 72%, p<0.001) compared to NHW women. The unadjusted 5-year OS for AIPA and NHW women were 56% vs. 43% in the overall population, and 53% vs. 41% among women with HGSOC, respectively. In multivariate analysis of the entire study population, AIPA women had a significantly better OS than NHW women (HR: 0.86, 95%CI: 0.79 - 0.94, p<0.001). Among women with HGSOC, a similar trend of better OS was noted in multivariate analysis among AIPA women compared to NHW (HR: 0.88, 95%CI: 0.77 - 1.01, p=0.07), although this did not reach statistical significance. Conclusion: The younger age at diagnosis, along with a generally better prognosis, among AIPA women compared to NHW women, suggests a possible enrichment of DNA-repair gene alterations among AIPA women. Citation Format: Aditi Karki, Sumeet Kumar Yadav, Muhammad Rafiqul Islam, Raja Pramanik, Ramila Shilpakar Dangol, Zeba Aziz, Sandhya Pruthi, Maryam Shahi, Jamie N. Bakkum-Gamez, Scott H. Kaufmann, Fergus J. Couch, Siddhartha Yadav. Clinical characteristics and survival outcomes of ovarian cancer among South Asian women in United States [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7118.

Breast cancer imposes a significant burden globally. While the survival rate is steadily improving, much remains to be elucidated. This observational, single time point, multiomic study utilizing genomics, proteomics, targeted and untargeted metabolomics, and metagenomics in a breast cancer survivor (BCS) and age-matched healthy control cohort (N = 100) provides deep molecular phenotyping of breast cancer survivors. In this study, the BCS cohort had significantly higher polygenic risk scores for breast cancer than the control group. Carnitine and hexanoyl carnitine were significantly different. Several bile acid and fatty acid metabolites were significantly dissimilar, most notably the Omega-3 Index (O3I) (significantly lower in BCS). Proteomic and metagenomic analyses identified group and pathway differences, which warrant further investigation. The database built from this study contributes a wealth of data on breast cancer survivorship where there has been a paucity, affording the ability to identify patterns and novel insights that can drive new hypotheses and inform future research. Expansion of this database in the treatment-naïve, newly diagnosed, controlling for treatment confounders, and through the disease progression, can be leveraged to profile and contextualize breast cancer and breast cancer survivorship, potentially leading to the development of new strategies to combat this disease and improve the quality of life for its victims.

Background We previously showed that the BRCA1 variant c.5096G>A p.Arg1699Gln (R1699Q) was associated with an intermediate risk of breast cancer (BC) and ovarian cancer (OC). This study aimed to assess these cancer risks for R1699Q carriers in a larger cohort, including follow-up of previously studied families, to further define cancer risks and to propose adjusted clinical management of female BRCA1*R1699Q carriers. Methods Data were collected from 129 BRCA1*R1699Q families ascertained internationally by ENIGMA (Evidence-based Network for the Interpretation of Germline Mutant Alleles) consortium members. A modified segregation analysis was used to calculate BC and OC risks. Relative risks were calculated under both monogenic model and major gene plus polygenic model assumptions. Results In this cohort the cumulative risk of BC and OC by age 70 years was 20% and 6%, respectively. The relative risk for developing cancer was higher when using a model that included the effects of both the R1699Q variant and a residual polygenic component compared with monogenic model (for BC 3.67 vs 2.83, and for OC 6.41 vs 5.83). Conclusion Our results confirm that BRCA1*R1699Q confers an intermediate risk for BC and OC. Breast surveillance for female carriers based on mammogram annually from age 40 is advised. Bilateral salpingo-oophorectomy should be considered based on family history.