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How do BRCA1 and BRCA2 mutations affect breast cancer risk?

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Precancerous growth in a human colon — cancer View through an endoscope of a polyp, a benign precancerous growth projecting from the inner lining of the colon.

BRCA1 and BRCA2 are tumor suppressor genes that play a vital role in repairing DNA damage and maintaining genetic integrity. Mutations in these genes hinder this repair process, significantly increasing the risk of developing breast cancer and other malignancies.1

For women in the general population, the lifetime risk of developing breast cancer is approximately 12 to 13 percent. In contrast, women who inherit a BRCA1 mutation face a 55 to 65 percent risk by age 70, while those with a BRCA2 mutation have a risk of roughly 45 percent. Furthermore, carriers who survive an initial breast cancer diagnosis have a significantly higher likelihood of developing the disease in the opposite breast (contralateral malignancy) compared to non-carriers.1

These mutations also affect men, increasing their risk of breast cancer to as much as 1.2 percent for BRCA1 and 7.1 percent for BRCA2 by age 70, compared to 0.1 percent in the general population. Individuals with these mutations may consider proactive health strategies, including increased screening, lifestyle modifications, or prophylactic surgery.12