The race, staging and clinical correlations with genetic mutations detected in breast cancer patients.

Abstract

e12547 Background: Genetic testing has been applied widely in oncology and guidelines and criteria have been established for selection of testing. We aimed to study the variants of genetic mutations detected in a cohort of breast cancer patients of multiple ethnicity background, and its pathoclinical correlations. Methods: Breast cancer patients who have had a genetic test performed between 1/1/2010 until 1/31/2022 were eligible. Results: Among 767 patients tested, 77 patients were found to have germline mutations, including BRCA 1 (n = 20), BRCA 2 (n = 19), PALB2 (n = 12), CHEK 2 (n = 6), ATM (n = 4), RAD50 (n = 4), and others (n = 12). The race and ethnic groups were White/Caucasian (n = 23), African American (AA) (n = 25), Asian (n = 13), Jewish (n = 12) and Hispanic (n = 4). Genetic testing were performed when the tumors were diagnosed of stage 1-2 in 77.8% in white + jewish, 100% in Asian, 75% in Hispanic patients, but only 64% in AA patients. Non metastatic tumors with BRCA 1/2 mutation had a distribution in stage 1, 2, and 3 to be 30%, 37.5%, 27.5% respectively, while that for PALB2 was 0%, 83.3%, 8.3% respectively. BRCA 1 cancers showed 61.9% triple negative, 23.8% ER+/Her-2 neg, 14.3% ER-/Her-2 + distribution, and BRCA 2 cancers showed 31.6% triple negative, 63.2% ER+/Her-2 neg, and 5.3% ER+/Her-2 + distribution. PALB2 cancers showed 16.7% triple negative, 58.3% ER+/Her-2 neg, and 25% ER+/Her-2 + distribution. 4 (5.2%) patients were male, who had BRCA 2 (n = 2), RAD 50 (n = 1), and APC (n = 1), 3 were ER+/Her-2 neg, and 1 was ER+/Her-2 +. If NCCN criteria is used for selection for genetic testing, 8 (10.4%) patients will not meet the test criteria. Conclusions: Performance of genetic testing was done in more than 77% of the patient in early stage 1-2 breast cancer, which is significantly lower in AA subgroup (64%). BRCA 1/2 cancers presented in all early stages, while PALB2 cancers were predominantly stage 2 at diagnosis. Triple negative cancers were most common in BRCA 1, but can present in BRCA 2 and PALB2 mutations . RAD 50 and APC mutations can cause male breast cancer. Applying NCCN guideline, 10% patients will be missed for testing.