The BRCA1 and BRCA2 genes are the most important tumor suppressor genes. The mutations occurring in these genes lead to familial cancer susceptibility patterns. This pattern inherited as autosomal dominant does not only predispose a person to breast cancer. BRCA1 and BRCA2-related hereditary breast and ovarian cancer syndromes are associated with increased risk for most commonly female and male breast cancer, ovarian cancer, and more rarely prostate cancer, pancreatic cancer, and malignant melanoma-like malignancies. In these genes, mutation-bearing cases carry a lifetime risk of malignancy of up to 80%. Its morbidity and mortality can be reduced through the preventive measures that can be taken after genetic diagnosis.
To date, more than 4,000 mutations have been identified in the BRCA1 and BRCA2 genes. These genes, which are somewhat difficult to analyse with the Sanger sequence analysis method, have become more workable with the use of next generation sequence analysis technology. Nevertheless, due to their size, investigating mutations in these genes is a significant problem.