Is Colon Cancer Hereditary?

Colorectal cancer, also known as colon cancer, is the second leading cause of cancer-related deaths in the United States for men and women combined. While most cases are sporadic (not inherited), about 5% to 10% of cases are hereditary, meaning they are passed down from parents to children through genes.

There are several inherited genetic syndromes associated with an increased risk of colorectal cancer. These include:

Lynch syndrome: Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is the most common inherited colorectal cancer syndrome. It is caused by mutations in certain genes, such as MLH1, MSH2, MSH6, and PMS2, which are involved in DNA repair. People with Lynch syndrome have a significantly increased risk of developing colorectal cancer, as well as other cancers, such as endometrial cancer, ovarian cancer, stomach cancer, and urinary tract cancers.

Familial adenomatous polyposis (FAP): FAP is a rare genetic disorder characterized by the growth of numerous polyps (benign growths) in the colon and rectum. These polyps can eventually develop into cancer if they are not removed. FAP is caused by mutations in the APC gene, which is involved in regulating cell growth and division.

MUTYH-associated polyposis (MAP): MAP is an inherited colorectal cancer syndrome caused by mutations in the MUTYH gene, which is involved in repairing damaged DNA. People with MAP have an increased risk of developing colorectal cancer, particularly at a young age.

Juvenile polyposis syndrome (JPS): JPS is a rare inherited disorder characterized by the growth of juvenile polyps in the colon and rectum. These polyps can sometimes develop into cancer, although the risk is lower than in other inherited colorectal cancer syndromes. JPS is caused by mutations in the SMAD4 and BMPR1A genes, which are involved in regulating cell growth and differentiation.

Hereditary colorectal cancer syndromes are typically inherited in an autosomal dominant manner, meaning that only one copy of the mutated gene (from either parent) is needed to cause the disorder. In some cases, however, a person may inherit two copies of a mutated gene, which can lead to a more severe form of the condition.

If you have a personal or family history of colorectal cancer or polyps, talk to your doctor about your risk and whether you should consider genetic testing. Genetic testing can identify mutations in genes associated with hereditary colorectal cancer syndromes and can help guide your medical care and management.