Background: Adenomatous polyposis coli (APC) gene is thought to play a key role in the majority of sporadic colorectal cancers developed through the chromosomal instability pathway. In 10–15% of CRC the defect of the mismatch repair genes (MLH1, MSH2), the microsatellite instability is the underlying mechanism for carcinogenesis. The aim of this study was the correlation of APC, MLH1 and MSH2 immunoexpression in different types of colon adenomas/polyps (A/P).
Materials and methods: We processed biopsies and surgical pieces of colon A/P and carcinoma developed in adenoma (CC). The APC, MLH1, MSH2 expression were graded, and used for establishing different immune phenotypes that have been compared by statistical tests. Results: The majority of tubular and tubulovillous adenomas have the MLH1+/MSH2+/APC+ immune phenotype, and the ratio of MLH1–/MSH2–/APC+ cases increases in case of hyperplastic polyps and serrated adenomas. A/P developing in the right colon and in patients below 40 years were more frequently MLH1–/MSH2–/APC+.
Conclusions: APC immunoexpression decreases in adenomas/polyps with dysplasia, and MLH1 and MSH2 expression is altered especially in hyperplastic polyps and serrated adenomas.