[Comprehensive application of various screening strategies of Lynch syndrome]

Lynch syndrome (LS), which is the most common hereditary colorectal cancer, accounts for about 3% of all colorectal cancers. However, due to its various clinical manifestations, it is difficult to be diagnosed. The diagnosis of LS requires comprehensive application of various screening criteria (such as the Amsterdam criteria, Bethesda criteria), predictive models, risk factors, immunohistochemistry test of mismatch repair (MMR) protein, microsatellite instability (MSI) detection, MLH1 methylation detection, BRAF gene mutation detection, germline gene mutation detection, and so on. LS can be diagnosed only after the identification of pathogenic germline mutation of MMR gene. The first-degree and second-degree relatives of LS patients are recommended to be tested for the identified mutant gene. For LS patients and gene mutation carriers, LS associated cancer can be detected early or even prevented by monitoring and preventive surgery. Reproductive techniques can be used to prevent this disease from being passed down to the next generation.