Cancer Genetics

Cancer genetics is one of the most impactful areas of genomic medicine, revealing how inherited DNA variants can significantly alter a person's lifetime risk of developing various cancers. While most cancers arise from acquired somatic mutations, approximately 5–10% of all cancers are driven by germline variants that are passed from parent to child and can be detected through a simple DNA test.

The most well-known cancer genes are BRCA1 and BRCA2. Women carrying pathogenic variants in these genes face a lifetime breast cancer risk of 45–72%, compared to roughly 12% in the general population, and an ovarian cancer risk of up to 44%. But BRCA is just the beginning — BRCA mutations also increase risk for prostate and pancreatic cancer in men. Genetic testing for BRCA variants has become standard of care, enabling preventive strategies ranging from enhanced screening to prophylactic surgery, as famously demonstrated by Angelina Jolie's preventive double mastectomy in 2013.

Beyond BRCA, the landscape of cancer genetics includes tumor suppressor genes like TP53 (Li-Fraumeni syndrome, conferring near-100% lifetime cancer risk), APC (familial adenomatous polyposis and colorectal cancer), and mismatch repair genes MLH1, MSH2, MSH6, and PMS2 (Lynch syndrome, which increases risk for colorectal, endometrial, ovarian, and gastric cancers). Oncogenes such as EGFR, KRAS, and HER2, while primarily relevant in somatic tumor profiling, also have germline variants that inform hereditary cancer risk and guide treatment selection through targeted therapies like trastuzumab and erlotinib.

Understanding your genetic predisposition to cancer empowers you to take proactive steps — whether that means more frequent screenings, lifestyle modifications, chemoprevention, or discussing risk-reducing procedures with your oncologist. By uploading your DNA data to Ask My DNA, you can check key cancer-associated variants and begin a data-driven conversation about your personal risk profile.