Association between Microsatellite instability (MSI) testing with clinicopathological findings of colorectal cancer patients

Abstract

Studies have shown that several molecular mechanisms are involved in the development of CRC tumors, among which microsatellite instability (MSI) is seen in 15% of cases. purpose of this study was to investigate the relationship between expression of microsatellite instability test (MSI) and clinicopathological findings of colorectal cancer patients. Method: 80 patients with definite diagnosis of colorectal cancer were included in the study. MSI test factors including CEA, PMS2, MLH1, MSH2 and MSH6 were evaluated by immunohistochemical method. Patients were divided into three categories of patients with high MSI (MSI-H), low MSI (MSI-L) and stable microsatellite (MSS) and relationship between patients' age, tumor type and location were evaluated by MSI test. Results: average age and gender of patients in different study groups did not differ significantly from each other. 8 (10%) patients were positive for MSH2, 3 (3.8%) for MSH6, 7 (8.8%) for PMS2 and 8 (10%) for MLH1. There was no significant difference in terms of tumor location, disease stage, disease TNM, metastasis location in positive metastasis cases, PD-L1 positivity and tumor differentiation between study groups. Patients in MSI-H, MSI-L and MSS groups did not differ significantly from each other. According to Kaplan-Meier diagram, median survival among MSI-H patients was not different from MSI-L and MSS. Causes of death included malignancy, ICH, and surgical complications.