Is colorectal cancer hereditary? It is reported that about 20% of colorectal cancers have family aggregation. People with a history of polyps and a family history of colon cancer who are at high risk must have regular colonoscopy over the age of 40, while for carriers of certain genetic defects, the age at which colonoscopy begins should be earlier and the interval between examinations should be reduced. Familial hereditary adenomatous colorectal cancer: polyps are prone to cancer The development of any disease will have two factors: exogenous and endogenous factors, endogenous factors refer to genetic factors, and at the same time, the disease will occur only when the exogenous factors work together. When it comes to endogenous factors, the main factor is hereditary: there is a kind of family hereditary adenomatous colorectal cancer, which is mainly due to the mutation of an oncogene called APC, and many polyps will grow in the intestine. Even if there are no bad habits, the fate of colorectal cancer cannot be avoided eventually. There is another kind of non-polyposis family hereditary colon cancer, which has no clinical signs and you can’t tell whether it is non-hereditary or hereditary colon cancer before it develops. It occurs in every generation in a family. The cause of the disease is related to the inactivation of the nucleic acid repair gene, a human genetic material. People will be exposed to many carcinogens during their lifetime, and these carcinogens will cause damage to nucleic acids, but our body has a strong repair function, and it will be normal when it is repaired. However, this group of people cannot repair the damage after being hit by carcinogens due to the problem of repairing genes, and then develop the disease. This part of tumor is genetic factor plays a decisive role and is less influenced by external factors. Hereditary colon cancer only accounts for about 15%, and non-polyposis familial colon cancer accounts for 2-3% of the overall colon cancer level. The majority of the cases are still non-hereditary colorectal cancers, and external causes play a major role. For non-hereditary colorectal cancer, there is no specific genetic abnormality, but rather a defect in certain genes. Because there are certain differences in the same gene between individuals, the most common is polymorphism of the gene. These differences can affect the activity of some enzymes, such as metabolizing enzymes of carcinogens, nucleic acid repair enzymes, etc. When enzyme activity is reduced, the chance of developing cancer is higher when receiving the same carcinogens. Although the majority of non-hereditary colorectal cancers are not heritable, this nucleic acid defect is heritable, i.e., the susceptibility to develop colorectal cancer is heritable. For this majority of people, the occurrence of colorectal cancer can still be avoided by maintaining good lifestyle habits. So, how to distinguish what kind of polyps are likely to become cancerous? Familial adenomatous polyps are not a problem if they are hyperplastic polyps. Familial adenomatous polyps are found in the whole intestine or even in the stomach, and can be detected through relevant tests. The polyps should be cut out as much as possible, and if they cannot be completely cut out, such patients should have annual colonoscopy for early detection of cancer. Some patients are carriers of tumor genes, which can be detected through genetic screening, and if there are genetic abnormalities, we will treat them as high-risk groups. Colorectal cancer gene screening is not routine in our country now, some units are only for research. Experts suggest that high-risk groups with history of polyps and family history of colon cancer must have regular colonoscopy over 40 years old, and for carriers of certain genetic defects, the age of starting colonoscopy should be earlier and the examination interval should be narrowed. Therefore, patients should pay more attention to the hereditary nature of colon cancer and have regular checkups to prevent the disease before it happens.