Detect Microsatellite Instability Status in Blood Sample of Advanced Colorectal Cancer Patients by Next-Generation Sequencing

The method to analyze the microsatellite instability (MSI) status by next-generation sequencing (NGS) has been established to assess the deficiency of DNA mismatch repair (MMR) system. The aim of our study is to evaluate the feasibility and reliability of this NGS method by testing the circulating tumor DNA (ctDNA) in blood sample of advanced colorectal cancer patients. If the result is positive, the MSI status could be easily learned without the acquisition of tissue samples.