MSH2, MSH6, MLH1 & PMS2 CORRELATION WITH CLINICOPATHOLOGICAL FEATURES IN COLORECTAL CARCINOMA : AN EXPERIENCE FROM A TERTIARY CARE ONCOLOGY CENTER

Abstract

Introduction- Colorectal carcinoma is common tumor with sporadic as well as familial association like Familial Adenomatous Polyposis (FAP) MUTYH-associated polyposis (MAP) and Lynch syndrome. Genetic analysis remains the gold standard for diagnosis of familial colorectal carcinomas. Aim- The present study was conducted in a tertiary care cancer hospital in India to evaluate Clinicopathological features in resected cases of colorectal cancer cases and their correlation withMLH1, MSH2, MSH6 & PMS2 by Immunohistochemistry. Material & Methods- The present study was carried out in department of pathology at regional cancer tertiary centre from February 2019 to June 2020. The cases were selected on basis of inclusion & exclusion criteria.MSH2, MSH6, MLH1 & PMS2 was assessed in all 100 cases, Results- The average age of the patients suffering from colorectal carcinoma (53 years) with male preponderance was noted. (M:F=1.9:1). Most common clinical symptoms were Abdominal pain (82%) . 9% of patient had a family history of cancer ( 5% GIT and 4% Non-GIT). Serum CEA level was ranging from 0.39 to 475. Mean CEA level was 28.3 and with 43.8 standard deviation. Ulceroproliferative (53%) is the most common type of growth pattern. Most common type was Adenocarcinoma (NOS) 70% & most common grade was Moderately Differentiated (56%). Intratumoral Lymphocytic response (ITL) was seen in 78% cases.70% cases were in < 10% range & 8% cases were in >10% range. Most common tumor stage was T3 (57%) & most common TNM stage was stage II (42%). Lymph node metastasis was seen in 42% cases. Out of 100 cases, 86% cases were MMR procient & 14% cases were MMR decient. We found combined loss of (MSH2+MSH6) in 3 cases (21.4%) , combined loss of (MLH1+PMS2) in 5 cases (35.7%), Combined loss of all the 4 markers in 2 cases (14.3%), Isolated loss of MSH2 in 1 (7.14%), & Isolated loss of MSH6 in 1 (7.14%), isolated loss of MLH1 in 1 (7.14%) & isolated loss of PMS2 in 1 (7.14%). Conclusion- MSI cases correlated with Family history of cancer, Moderate degree of Differentiation, Adenocarcinoma (NOS) type, Intratumoral Lymphocytic Inltrate, Ulceroproliferative growth pattern & Right side lesion. There was no difference in MMR protein loss based on patients age, gender, treatment history, tumor stage , lymph node metastasis & TNM staging. The Clinicopathological features and IHC dictate in selection of cases for MSI testing in a resource limited developing countries where lack of expertise and cost are concerns.