Clinicopathological correlation between mismatch repair gene expression and colorectal cancer in Bangladesh

Background: Patients with colorectal cancer (CRC) vary greatly in their clinical prognosis even when their tumors are at the same TMN stage. This variation is most likely caused by molecular tumor heterogeneity. Several studies have found a connection between the MMR status and the clinicopathological features of colorectal cancer. Despite the significance of MSI-H/dMMR and pMMR/MSS status in clinical decision making, the rates of microsatellite instability (MSI) and mismatch repair (MMR) testing in clinical practice are still low, even in high-risk populations. This study aims to evaluate the clinicopathological association between the MMR gene expression pattern and CRC. Methods: This cross-sectional study comprised of patients with rectal cancer, within the period of January 2023 to December 2023. After diagnosis of colorectal cancer samples taken and MSI and MMR study is done. Clinicopathological data is correlated with the gene expression. Results: Total 63 patients were included. Males 61.9% (n=39) and female 38.1% (n=24) of the study population. Mean age is 49.7±12.6 years with the range of 18 to 77 years. Rectal cancer is the most diagnosed case (n=19, 30.2%). Most mutation is in right side cancers (n=15, 68.2%). MLH1 as a single gene and MLH1+PMS2 as a dimer is the most frequent mutation. Isolated MLH1 and PMS2 mutation in found in six patients. 18 patients MSI-H. Conclusions: In clinical practice, MSI should be widely encouraged as it is vitally important. The molecular classification of CRC may identify patient subgroups at varying risk of recurrence and death and categorized patients for whom personalized approaches to therapy may beneficial.