The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease‐associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population‐specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad‐based oncogenetic testing in some populations.

PURPOSE Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi), is approved for the treatment of human epidermal growth factor receptor 2 (HER2)–negative metastatic breast cancer (MBC) in germline (g) BRCA1/ 2 mutation carriers. Olaparib Expanded, an investigator-initiated, phase II study, assessed olaparib response in patients with MBC with somatic (s) BRCA1/ 2 mutations or g/s mutations in homologous recombination (HR)–related genes other than BRCA1/2. METHODS Eligible patients had MBC with measurable disease and germline mutations in non- BRCA1/ 2 HR-related genes (cohort 1) or somatic mutations in these genes or BRCA1/ 2 (cohort 2). Prior PARPi, platinum-refractory disease, or progression on more than two chemotherapy regimens (metastatic setting) was not allowed. Patients received olaparib 300 mg orally twice a day until progression. A single-arm, two-stage design was used. The primary endpoint was objective response rate (ORR); the null hypothesis (≤ 5% ORR) would be rejected within each cohort if there were four or more responses in 27 patients. Secondary endpoints included clinical benefit rate and progression-free survival (PFS). RESULTS Fifty-four patients enrolled. Seventy-six percent had estrogen receptor–positive HER2-negative disease. Eighty-seven percent had mutations in PALB2, s BRCA1/ 2, ATM, or CHEK2. In cohort 1, ORR was 33% (90% CI, 19% to 51%) and in cohort 2, 31% (90% CI, 15% to 49%). Confirmed responses were seen only with g PALB2 (ORR, 82%) and s BRCA1/ 2 (ORR, 50%) mutations. Median PFS was 13.3 months (90% CI, 12 months to not available/computable [NA]) for g PALB2 and 6.3 months (90% CI, 4.4 months to NA) for s BRCA1/ 2 mutation carriers. No responses were observed with ATM or CHEK2 mutations alone. CONCLUSION PARP inhibition is an effective treatment for patients with MBC and g PALB2 or s BRCA1/ 2 mutations, significantly expanding the population of patients with breast cancer likely to benefit from PARPi beyond g BRCA1/ 2 mutation carriers. These results emphasize the value of molecular characterization for treatment decisions in MBC.

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Background We examined the longitudinal associations between changes in cardiovascular biomarkers and cancer therapy–related cardiac dysfunction ( CTRCD ) in patients with breast cancer treated with cardotoxic cancer therapy. Methods and Results Repeated measures of high‐sensitivity cardiac troponin T (hs‐ cTnT ), NT ‐pro BNP (N‐terminal pro‐B‐type natriuretic peptide), myeloperoxidase, placental growth factor, and growth differentiation factor 15 were assessed longitudinally in a prospective cohort of 323 patients treated with anthracyclines and/or trastuzumab followed over a maximum of 3.7 years with serial echocardiograms. CTRCD was defined as a ≥10% decline in left ventricular ejection fraction to a value <50%. Associations between changes in biomarkers and left ventricular ejection fraction were evaluated in repeated‐measures linear regression models. Cox regression models assessed the associations between biomarkers and CTRCD . Early increases in all biomarkers occurred with anthracycline‐based regimens. hs‐ cTnT levels >14 ng/L at anthracycline completion were associated with a 2‐fold increased CTRCD risk (hazard ratio, 2.01; 95% CI , 1.00–4.06). There was a modest association between changes in NT ‐pro BNP and left ventricular ejection fraction in the overall cohort; this was most pronounced with sequential anthracycline and trastuzumab (1.1% left ventricular ejection fraction decline [95% CI , −1.8 to –0.4] with each NT ‐pro BNP doubling). Increases in NT ‐pro BNP were also associated with CTRCD (hazard ratio per doubling, 1.56; 95% CI , 1.32–1.84). Increases in myeloperoxidase were associated with CTRCD in patients who received sequential anthracycline and trastuzumab (hazard ratio per doubling, 1.28; 95% CI , 1.04–1.58). Conclusions Cardiovascular biomarkers may play an important role in CTRCD risk prediction in patients with breast cancer who receive cardiotoxic cancer therapy, particularly in those treated with sequential anthracycline and trastuzumab therapy. Clinical Trial Registration URL : https://www.clinicaltrials.gov/ . Unique identifier: NCT 01173341.

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