Diagnosis of Lynch Syndrome Based on Next-generation Sequencing in Colorectal Cancer

Overview

The purpose of this study is to determine the proportion of patients diagnosed with Lynch syndrome in colorectal cancer patients with the loss of staining by immunohistochemistry (IHC) of any of the mismatch repair (MMR) proteins. Besides, this study aims to test the specificity and the sensitivity of detecting microsatellite instability (MSI) by next-generation sequencing, and to find out the consistency between IHC and MSI in colorectal cancer patients in China. In addition, researchers want to analyze the clinical characteristics and germline mutation of Lynch syndrome in Chinese population.

1. Detect microsatellite instability (by next-generation sequencing and PCR capillary electrophoresis) and germline mutation (by next-generation sequencing) in probands. 2. Analyze the test outcome with clinical and family information to evaluate the germline mutation status preliminarily: likely pathogenic germline mutation, variant of uncertain significance, non-pathogenic germline mutation. 3. Verify the germline mutation in blood relatives whose proband has known likely pathogenic germline mutation or variant of uncertain significance. 4. Diagnose pathogenic germline mutation and non-pathogenic germline mutation based on clinical characteristics, family information and germline mutation test outcomes (including the outcomes of probands and blood relatives). Diagnose Lynch syndrome and the pathogenic germline mutation carriers in the included population. 5. Analyze the specificity and the sensitivity of detecting microsatellite instability (MSI) by next-generation sequencing; and analyze the consistency between IHC and MSI. 6. Analyze the clinical characteristics and germline mutation of Lynch syndrome in Chinese population.

Conditions

Interventions