Diagnosis of Lynch Syndrome Based on Next-generation Sequencing in Patients Meeting Chinese Lynch Syndrome Criteria

For probands, the inclusion criteria： all of the following three points should be satisfied: 1. One of the colorectal cancer patients from families meeting Chinese Lynch syndrome criteria. Chinese Lynch syndrome criteria: In a pedigree, there were at least 2 patients with histological-proven colorectal cancer, and among these, at least two patients are first-degree relatives of each other. Besides, any one of the following three points should be satisfied in the pedigree: A. at least one patients with multiple primary colorectal carcinoma/adenoma, either synchronously or metachronously. B. at least one colorectal cancer diagnosed before 50 years old. C. in the pedigree, at least one patient diagnosed with other Lynch syndrome associated cancer (ie, gastric, endometrial, small bowel, ureter, or renal-pelvic, ovarian and hepatobiliary cancers). 2. With sufficient blood to test; 3. Agree to provide basic information, clinical information and family history of cancer information. For probands, the exclusion criteria: With at least one blood relative with known pathogenic germline mutation(s). For blood relatives verifying germline mutation, the inclusion criteria： all of the following three points should be satisfied: 1. First- to second-degree blood relatives of probands with germline mutation(s). 2. With sufficient blood to test. 3. Agree to provide basic information, clinical information and family history of cancer information. For blood relatives verifying germline mutation, the exclusion criteria: Blood relatives who refuse to test.