Mismatch repair gene status by immunohistochemistry in endometrial hyperplasia, endometrial intraepithelial neoplasia and endometrial carcinoma

Background: Over 83% of uterine corpus tumors are endometrioid carcinomas. The WHO 5th edition of Endometrial Tumors, which considers morphology and molecular pathogenetic pathways, includes the four types of endometrial carcinomas that are identified by the Cancer Genome Atlas (TCGA). These 4 groups include, 1: POLE mutations, 2. Low Copy Number Alteration 3. Microsatellite Instability and 4. High Copy Number Alteration and P53 mutationThis research aims to examine the frequency of microsatellite instability (MSI) and mismatch repair gene (MMR) in hyperplasia of endometrium, Endometrial Intraepithelial Neoplasm and carcinoma of endometrium. To evaluate association of MMR with clinical parameters and histopathological findings.Methodology: Clinical, radiological and laboratory data was extracted from computerized medical records. Patients undergoing endometrial biopsy for AUB on hormone replacement therapy, with ovarian tumours, cervical tumours and products of conception with coagulopathies were excluded from the study.Results: Total number biopsies studied during study period were 85cases which included 8cases of normal endometrium, 37cases of benign hyperplasia, 7cases of endometrial intraepithelial Neoplasm (EIN) and 33cases of endometrial carcinoma. Mean age affected was 42.8yrs. Menorrhagia and post-menopausal bleeding was common clinical presentation. Endometrial thickness ranged between 6mm to 40mm. Mismatch repair gene deficiency(dMMR) was noted in endometrial carcinoma and endometrial intraepithelial neoplasia (EIN).Conclusion: Present study concludes endometrial thickness is an important radiological parameter to assess the pathological state of endometrium. dMMR/MSI is known to occur in sporadic endometrial carcinomas, knowing MMR/MSI status helps in targeted therapy. Hence study recommends to perform MMR by immunohistochemistry on all carcinoma diagnosed on endometrial biopsy.