The effect of Entamoeba histolytica Lectin Antigen and MicroRNA-643 on the development of microsatellite instability (MSI) in Colorectal Adenocarcinoma

Abstract Globally, Entamoeba histolytica remains a leading cause of death. The impact of protozoa as environmental factors in microsatellite instability (MSI) remains largely unexplored, as are miRNAs as potential biomarkers for amoeba and in the context of colorectal disease. In this study, we investigated the relationship between the antigenic structure of the Eh-lectin and the altered expression of miRNA-643 and XIAP, a gene involved in apoptosis inhibition. The study aimed to detect E. histolytica, miRNA-643, XIAP, and MSI in 150 colorectal cancer biopsy samples. To achieve this, a multi-faceted approach employing immunohistochemistry (IHC), Multiplex PCR, RT-qPCR, and Real-Time PCR were utilized. For enhanced MSI diagnosis precision, PCR-Multiplex was performed concurrently with IHC. Among the 150 colorectal cancer biopsy samples analyzed, 39 (28 MSI-H and 11 MSI-L) exhibited microsatellite instability (MSI), while the remaining 111 were MSI-negative. Notably, co-occurrence of MSI and E. histolytica antigen was observed in 11 samples. These samples (positive for both MSI and E. histolytica antigen) showed an increased expression of miRNA-643, contrasting with XIAP expression. The concurrence of microsatellite instability (MSI) with E. histolytica antigen positivity and elevated miRNA-643 expression, contrasted with diminished XIAP inhibitor gene levels, in colorectal adenocarcinoma biopsy samples, strongly supports the hypothesis that this protozoan parasite plays a role in MSI development, through its potential involvement in apoptosis.