e12588 Background: We assessed the prevalence of family history and its association with germline BRCA1/2mutation status/location and age at onset in triple-negative breast cancer (TNBC) patients. Methods: 266 patients with TNBC < 60 years unselected for family history of cancer were enrolled and germline DNA was sequenced to identify mutations. Family pedigrees were prospectively collected from these patients. Logistic regression was used to investigate family history and its association with mutation type/location and age at onset. ROC curves were constructed to determine good predictors of BRCAmutations. Results: BRCA mutations were identified in 18.0% of all patients (15.0% BRCA1, 3.0% BRCA2). BRCA1 carriers have a significantly earlier age at onset than non-mutation carriers (40 vs 49 years; p < .001). While 39/124 (31.4%) patients with family history of cancer carried a BRCA1/2 mutation, 9/142 (6.3%) BRCA carriers had no family history of cancer. BRCA1 carriers with ≥1BC in the family are commonly identified in the breast cancer cluster regions (53.1%). BRCA2 carriers more commonly cluster within the ovarian cancer regions. Of note, this difference was not statistically significant. Women with mutations in BRCA1 OCCR are diagnosed at a younger age. TNBC diagnosed ≤45 years with ≥1BC and ≥1OC in the family are good predictors of BRCA1 mutation (AUC 0.867). Conclusions: Young women with TNBC and a family history of BC and OC are likely to have a BRCA mutation. Specific BRCA mutation locations may add to the identification of a subgroup of TNBC patients with a relatively higher risk of subsequent ovarian cancer. Identification of high-risk TNBC patients with BRCA1 mutation will enable clinicians to optimize cancer management for this phenotype, but will require further validation in larger studies.
The Family-History of Cancer-Patients
