Microsatellite Instability in Epithelial Cells of Gastric Polyp

Microsatellite instability (MSI) is a predisposition to mutations resulting from impaired DNA mismatch repair and is an important factor in the occurrence and development of tumors. The aim of this study was to describe MSI using markers MLH1, PMS2, MSH2, and MSH6 in epithelial cells of benign gastric lesions. It was found that the phenomenon of microsatellite instability was observed in polypoid gastric lesions, except for foveolar hyperplasia, in the following percentages: in hyperplastic polyps – low-level MSI (40%), high-level MSI (19%), and absence of MSI (41%); in foveolar-type adenoma with low-grade dysplasia – low-level MSI (18.8%), high-level MSI (31.2%), and absence of MSI (50%); in foveolar-type adenoma with high-grade dysplasia – low-level MSI (0%), high-level MSI (42%), and absence of MSI (58%). The highest response was observed in foveolar-type adenoma with high-grade and low-grade dysplasia, suggesting that microsatellite instability may play a role in the process of malignant transformation.