Hereditary nonpolyposis colorectal cancer. The screening criteria of hereditary nonpolyposis colorectal cancer in China: at least 2 patients with colorectal cancer with definite histopathological diagnosis in the family, in which there was a relationship between parents and children or siblings. Meet one of the following:
1 at least 1 patient with multiple colorectal cancer (including adenoma).2 at least one patient developed earlier than 50 years old.3 at least one patient suffered from HNPCC-related extraintestinal malignant tumors (gastric cancer, endometrial cancer, small intestinal cancer, ureteral cancer, ovarian cancer, hepatobiliary system cancer).The China hereditary Colorectal Cancer Cooperation Group recommends that families that meet the Chinese HNPCC screening criteria should undergo immunohistochemical study of hMLH1 and hMSH2 genes and detection of microsatellite instability (MSI) when laboratory conditions permit. If both are negative, there is no need for mutation analysis; if one of them is positive, further germline mutation analysis of hMLH1 and hMSH2 genes (germlinemuta-tion) will be performed.Once the mutation is clearly diagnosed, the patient's first-degree relatives should undergo the same test. All individuals who may have HNPCC should undergo colonoscopy every 1-2 years from the age of 20 to 25 or the youngest age in the family to be diagnosed as HNPCC minus 10 years, and once a year from the age of 40. In addition, HNPCC is prone to extra-intestinal tumors. Once diagnosed as HNPCC, extra-intestinal malignant tumors must be screened at the same time.
