BRCA1 and neoplasm: Among these, BRCA1/2 gene defects lead to HRR dysfunction, rendering tumor cells highly sensitive to platinum‐based agents; MMR system deficiencies enhance tumor cell sensitivity to alkylating agents by inducing Microsatellite Instability (MSI) and neoantigen generation; and ATM/ATR signaling pathway dysregulation impairs DDR capabilities, thereby exacerbating genomic instability.