Describe the general role of BRCA1/BRCA2 in HBOC and why testing these genes matters for risk management.

• A. They confer high risk for breast and ovarian cancers; identifying pathogenic variants informs intensified screening, risk-reducing strategies, and family cascade testing.
• B. They are associated with colorectal cancer only; testing does not affect management.
• C. They are low-risk genes; testing rarely informs management.
• D. They affect male cancer risk only.

Answer: (A)

BRCA1 and BRCA2 are high-penetrance HBOC genes that encode proteins essential for repairing double-strand DNA breaks through homologous recombination. When pathogenic variants are present, the ability to fix DNA damage is compromised, leading to genomic instability and substantially higher risks of breast and ovarian cancers across a person’s lifetime (with BRCA1 often linked to a higher ovarian cancer risk and earlier-onset breast cancer, and BRCA2 also markedly increasing breast cancer risk and affecting other cancer risks, including male breast cancer and pancreatic cancer).

Testing these genes matters for risk management because identifying a pathogenic variant guides personalized surveillance and preventive strategies. Individuals with these variants typically pursue intensified screening, such as annual MRI in addition to mammography starting at a younger age, and consider risk-reducing options like prophylactic mastectomy or risk-reducing salpingo-oophorectomy based on age, family history, and specific mutation. It also enables cascade testing to identify and inform relatives who may benefit from earlier surveillance or preventive measures. This is why the test result has clear implications for how someone monitors and reduces their cancer risk, rather than implying no impact on management or affecting only other cancer types.