BRCA1 and metastatic malignant neoplasm: We identify inactivation of BRCA1, BRCA2, RAD51C, and PALB2 as the most frequent genetic cause of HRD pan-cancer in both primary and metastatic cancer, with the latter two genes resulting in the same mutational footprints as BRCA2 (consistent with the findings of recent studies in breast cancer11,12).