Molecular genetics and management strategies in hereditary cancer syndromes

The origin, characteristics, and lifetime risk for the following five types of hereditary cancer (HCS) syndromes are briefly described in this review: hereditary breast and ovarian cancer (HBOC) syndrome, familial adenomatous polyposis (FAP), and hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, hereditary diffuse gastric cancer (HDGC) syndrome, and medullary thyroid carcinoma (MTC). Most are caused by mutations in tumor suppressor genes. In HCS, a single copy of the mutated tumor suppressor gene is inherited, and mutation of the second wild type allele of the gene is required for tumorigenesis. Patients with HCS have a higher than normal risk of a second malignancy. Management strategies to address increased cancer risk in HCS include genetic counseling and testing, targeted surveillance, chemoprevention, and prophylactic surgery. Genetic testing for high-risk family members is strongly recommended. Available data indicate surgical prophylaxis is more successful than surveillance in reducing cancer risk in carriers of BRCA, CDH1, APC, and RET mutation.