Abstract

Endometrial carcinoma is the 4th most commonly diagnosed gynecologic malignancy in the world and 11th most common in India [1]. Traditionally, endometrial carcinomas have been divided into two types. Type I-low grade, estrogen related, often clinically indolent, endometrioid carcinomas. Type II-non-endometrioid, clinically aggressive carcinomas that are unrelated to estrogen stimulation and include serous and clear cell carcinomas. This classification is not useful for tumor stratification because of significant overlap in various features with respect to high grade tumors of either types. Recent advances on genomic studies have classified endometrial carcinoma into 4 subtypes: 1. With Pole (DNA polymerase epsilon) mutations. 2. Microsatellite instability (MSI). 3. Showing low copy number alterations. 4. Tumors with high copy number alterations and TP53 mutations. Integration of molecular characteristics with morphologic features helps to stratify patients to predict prognosis. MSI can be identified by IHC which is efficient, relatively simple and cost effective. The present study is proposed to evaluate the morphological features of endometrial cancers and to analyze their profile based on loss of immunostaining for MMR proteins. Methods: A prospective study for a period of 2 years and 3 months from August 2020 to November 2022 was conducted in the Department of Pathology from Government General Hospital, Kakinada. A total of 50 endometrial samples were collected. Results: On histopathological examination 80% of cases were diagnosed as Type 1 endometrial carcinoma and 20% were type 2 endometrial carcinomas. On IHC for MMR protein expression, 22% cases showed loss of one or more MMR proteins. All of these deficient MMR cases were endometrioid type. Loss of MLH1 and PMS2 was the most common abnormality detected in deficient MMR tumors. Conclusion: Detecting MMR protein loss in endometrial carcinomas by IHC is an efficient, relatively simple and economical method. It needs to be routinely performed in all cases of endometrial carcinomas.

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