CHEK2 Gene Mutations: Cancer Risk
Cancer Risks Associated with Inherited Mutations
Cancer risks may vary based on your specific mutation and family history. NCCN notes that some mutations (for example a mutation known as IIe157Thr) may be associated with lower breast cancer risks than other mutations. If you have tested positive for an inherited mutation, we recommend that you speak with a genetics expert who can look at your personal and family history of cancer and can help you choose the best plan for managing your cancer risk. Note that when we use "men" and "male" we are referring to people assigned male at birth. When we use "women" and "female" we are referring to people assigned female at birth.
Breast cancer risk
- Women have a lifetime risk of 20-40 percent.
- For women who have already been diagnosed with breast cancer and who have not had mastectomies, the risk for a second diagnosis over a 10-year period is about 6-8 percent.
- Experts believe there is an increased risk for male breast cancer, but the exact risk is unknown.
Colorectal cancer risk
In the past, the NCCN guidelines listed colorectal cancer as increased for people with a mutation. The 2024 NCCN Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric guidelines were updated to indicate no increased risk for colorectal cancer with a mutation. These new guidelines recommend that people with mutations should consider family history and other factors to understand their risk for colorectal cancer and make decisions about their care.
Other cancer risks for people with a mutation
Some research has linked mutations to other cancer risks, including and thyroid cancer. More research is needed to prove these links.
It is important to note that cancer risks are estimates over the course of a person's lifetime. Your lifetime risk and risk over the next five years will vary depending on:
- current age
- sex assigned at birth
- specific mutation
- personal and family health history
- diet, exercise, lifestyle and other factors
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