Cancer Genetics Mutations Other Genes
Inherited genetic mutations that increase the risk of breast cancer
About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they result directly from gene changes (mutations) passed on from a parent. The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 or BRCA2 gene. In normal cells, these genes help make proteins that repair damaged DNA. Mutated versions of these genes can lead to abnormal cell growth, which can lead to cancer.
On average, a woman with a BRCA1 or BRCA2 gene mutation has up to a 7 in 10 chance of getting breast cancer by age 80. Women with one of these mutations are more likely to be diagnosed with breast cancer at a younger age, as well as to have cancer in both breasts. Women with one of these gene changes also have a higher risk of developing ovarian cancer and some other cancers. Men who inherit one of these gene changes also have a higher risk of breast and some other cancers.
In the United States, BRCA mutations are more common in Jewish people of Ashkenazi (Eastern Europe) origin than in other racial and ethnic groups, but anyone can have them. Other gene mutations can also lead to inherited breast cancers. These gene mutations are much less common, and most of them do not increase the risk of breast cancer as much as the BRCA genes.
Source: “Inheriting certain gene changes” (American Cancer Society)
Certain gene mutations increase the risk of Triple-Negative Breast Cancer (TNBC)
Mutations in the following genes have been linked to increased risk for breast cancer in women:
- BARD1 (especially triple-negative breast cancer)
- BRCA1 (frequently linked to triple-negative breast cancer)
- CDH1 (frequently linked to lobular breast cancer)
- NF1 (only in people with neurofibromatosis)
- RAD51C (especially triple-negative breast cancer)
- RAD51D (especially triple-negative breast cancer)
Mutations in the following genes may also be linked to increased breast cancer risk, but more research is needed to confirm this.
- BRIP1 (especially triple-negative breast cancer)
- NBN (only in people with a 657del5 mutation)
Mutations in the following genes have been linked to breast cancer risk in men:
Source: “Genes with inherited mutations linked to breast cancer” (FORCE: Facing Hereditary Cancer Empowered)
DNA repair defects
Sometimes, endometrial cancer may seem to “run in a family.” We now know that some of these families have a higher risk for this cancer because they have an inherited defect in certain genes that normally help repair damage to DNA. If these repair enzymes aren’t working properly, damage to DNA is more likely to persist and cause cancer.
DNA repair defects like this have also been found in endometrial cancer cells from women who haven’t inherited them.
One of the normal genes responsible for suppressing tumor growth, called PTEN, is often abnormal in endometrial cancers. And we know that endometrial cancers without other tumor suppressor genes (or with inactive ones), like the KRAS and the TP53 gene, tend to be more likely to come back after initial treatment.
Source: “What’s New in Endometrial Cancer Research?” (American Cancer Society)
Women born with mutations in the genes linked to endometrial cancer not only have a high lifetime risk, but they’re also more likely to develop the cancer at a young age. The genes linked to endometrial cancer risk include: