Abstract PO4-14-04: Comprehensive genomic profiling results in patients with metastatic breast cancer due to germline BRCA1/2 status and their HER2-low status

Abstract Objective: To determine the usefulness of comprehensive genomic profiling testing and the percentage of HER2-low in patients with germline BRCA1/2 (gBRCA1/2) variants metastatic breast cancer. Methods: We included 3404 patients with metastatic recurrent breast cancer who underwent CGP testing from June 2019 to June 2023 in Japan. We examined the proportion of patients with or without recommended therapy, the proportion of patients who received matched therapy, and the proportion of patients with HER2 low by gBRCA1/2 variant due to CGP testing. RESULTS.: Of the 3404 patients, 69 (2.0%) had gBRCA1, 136 (4.0%) had gBRCA 2, 5 (0.1%) had gBRCA1 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-14-04.