Hereditary Cancer Syndromes: Genetic Risks, Examples, and Testing

5–10% of cancers are hereditary—caused by germline mutations in cancer-predisposing genes. Inheritance does not guarantee cancer; penetrance varies with lifestyle, environment, and modifier genes.

Major Syndromes

• HBOC (BRCA1/2): Breast, ovarian, prostate, pancreatic cancer.
• Lynch syndrome (MMR genes): Colorectal, endometrial, gastric, ovarian.
• Li-Fraumeni (TP53): Sarcomas, breast, brain, adrenocortical.
• FAP (APC): Colorectal polyposis, duodenal, thyroid.
• Retinoblastoma (RB1): Pediatric eye cancer.
• Others: PALB2, CHEK2, ATM, CDKN2A, etc.

Action

Family history suggestive? Seek genetic counseling. Testing guides personalized screening (earlier/more frequent), risk-reducing surgery, chemoprevention, and cascade testing for relatives.