Molecular Screening for BRCA1 and BRCA2 Gene Mutations in Female Breast Cancer Patients at the National Hospital Abuja

Hereditary breast cancer accounts for approximately 5-10% of all breast cancer cases globally, with pathogenic variants in the BRCA1 and BRCA2 genes conferring substantially elevated lifetime risk. In Nigeria, breast cancer is the most commonly diagnosed cancer in women, yet molecular genetic data on BRCA mutation prevalence are extremely limited. This study screened female breast cancer patients attending the oncology clinic at National Hospital Abuja, Federal Capital Territory, for BRCA1 and BRCA2 mutations. Peripheral blood was collected from 80 consenting patients with histologically confirmed breast cancer and a reported family history of breast or ovarian cancer. Genomic DNA extraction was followed by PCR amplification of BRCA1 exons 11, 20, and 24, and BRCA2 exons 11 and 27. Amplicons were sequenced by Sanger sequencing and variants annotated against the ClinVar database. Pathogenic or likely pathogenic variants were identified in 16.25% of participants, with BRCA2 mutations (62.5%) more frequent than BRCA1 (37.5%) among variant carriers. Novel variants of uncertain significance (VUS) were found in an additional 12.5% of participants. These findings support expanding hereditary cancer genetic counseling services at National Hospital and other federal tertiary institutions. Keywords: BRCA1, BRCA2, breast cancer, mutation screening, National Hospital Abuja.