Carcinogenic form and characteristics of BRCA pathogenic variant breast cancer

Hereditary breast and ovarian cancer (HBOC) syndrome is caused by germline mutations in the BRCA1 and BRCA2 genes, which play critical roles in DNA double-strand break repair. Pathogenic variants (PVs) in these genes lead to homologous recombination deficiency (HRD), genomic instability, and increased cancer risk. BRCA1-associated breast cancers are predominantly triple-negative breast cancer (TNBC) with aggressive behavior, and BRCA2-mutated cases are mostly hormone receptor-positive and share similarities with sporadic luminal tumors. Genetic testing for BRCA PVs is crucial for identifying at-risk individuals and enabling risk-reducing interventions and personalized treatment strategies. In this review, we discuss the carcinogenic form and characteristics of BRCA PV-carrier breast cancer, focusing on BRCA-associated hereditary breast cancer and addressing its clinical characteristics and molecular mechanisms. Personalized treatment approaches that integrate patients' BRCA status with their tumor biology are essential for optimizing patient outcomes.