Final answer:
Women with harmful mutations in BRCA1 have a 55-65% risk of developing breast cancer by age 70, significantly higher than the 12% risk in the general population. BRCA1 mutations are often associated with a higher incidence of certain types of breast cancer, while BRCA2 mutations have broader cancer associations. Both genes play critical roles in DNA repair.
Step-by-step explanation:
The question pertains to the incidence of breast cancer in individuals with mutations in the BRCA1 and BRCA2 genes. Inheriting mutations in either BRCA1 or BRCA2 significantly increase the risk of breast and ovarian cancer. It is important to note that while BRCA1/2 mutations elevate the risk of developing cancer, they do not guarantee it, as environmental factors also play a role. The risk of breast cancer by age 70 is approximately 55-65% for women with a harmful mutation in BRCA1, compared to 12% for the general population.
There are differences in the cancer risks associated with each gene: Generally, BRCA1 mutations are more strongly associated with breast cancer, especially triple-negative breast cancer, while BRCA2 mutations are associated with a wider range of cancers, including male breast cancer and certain other cancers. Additionally, the function of these genes is crucial for DNA repair, and when mutated, the impaired DNA repair mechanisms increase the likelihood of cancer development.