Which genetic mutations are associated with an increased risk for breast cancer?

The association of BRCA1 and BRCA2 mutations with an increased risk of breast cancer is well-documented in scientific literature. These two genes are crucial for the repair of DNA, specifically in repairing double-strand breaks through a process known as homologous recombination. When mutations occur in these genes, the repair mechanisms are compromised, which can lead to the accumulation of additional mutations in other genes that regulate cell growth and division. This accumulation increases the likelihood of developing breast cancer, as well as ovarian cancer, in individuals who carry these mutations.

Research has shown that individuals with a harmful mutation in either BRCA1 or BRCA2 can have a significantly higher lifetime risk of developing breast cancer compared to the general population. For example, women with a BRCA1 mutation have an estimated 55-65% chance of developing breast cancer by age 70, while those with BRCA2 mutations have approximately a 45% chance. This stark increase in risk underscores the critical role that these genes play in breast cancer susceptibility.

The other gene mutations mentioned, such as APC and TP53, are associated with different types of cancers but are not specifically tied to increased risks of breast cancer in the same way. Similarly, KRAS and HER2 are