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

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.