Expression of mismatch repair proteins in urothelial carcinoma of the urinary bladder

Abstract

Background: Urothelial carcinoma of the urinary bladder (UCUB) is a frequently diagnosed malignancy. Mismatch repair (MMR), a proofreading machinery of the DNA, prevents tumorigenesis. The role of MMR deficiency in UCUB in eastern Indian population is not known. Methods: Immunohistochemistry panel for MLH1, PMS2, MSH2, and MSH6 (MMR proteins) was performed on the biopsy specimens of UCUB (N=100). Results: MMR deficiency by immunohistochemistry was demonstrated in two cases (2%). One case showed deficiency of MSH2 and MSH6 and the other case showed the deficiency of all four mismatch proteins. Both cases showed high-grade invasive urothelial carcinoma by histomorphology. Conclusion: The prevalence of MMR deficiency by immunohistochemistry is 2% in eastern Indian population.