The prevalence of germline mutations in Chinese colorectal cancer patients with mismatch repair deficiency.

e13518Background: Mismatch repair deficiency (dMMR) assessed by microsatellite instability (MSI) or immunohistochemistry (IHC) is a feature of Lynch syndrome, a major hereditary colorectal cancer (CRC). Chinese Lynch syndrome criteria was proposed based on the decreasing family numbers: In a pedigree, it should have at least 2 CRCs, and at least 2 of them are first-degree relatives of each other. Besides, any one of following criteria should be met: 1) at least 1 CRC should have multiple primary synchronous/metachronous colorectal carcinoma/adenoma; 2) at least 1 CRC should be diagnosed before 50 years old; 3) in the pedigree, at least 1 should be diagnosed with other Lynch syndrome-related cancer (i.e. gastric, endometrial, small bowel, ureter, or renal-pelvic, ovarian and hepatobiliary cancers). The purpose of this multi-center study is to derive prevalence of germline mutations in Chinese dMMR CRC, especially taking different screen criteria for Lynch syndrome into consideration. Methods: ColonCore pan...