Role of Immunohistochemical Markers MLH1, MSH2, PMS2 in Identifying Microsatellite Instability in Colorectal Carcinoma

Shobija, R (2020) Role of Immunohistochemical Markers MLH1, MSH2, PMS2 in Identifying Microsatellite Instability in Colorectal Carcinoma. Masters thesis, Madras Medical College, Chennai.


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BACKGROUND: Colorectal cancers are a leading cause of mortality and morbidity throughout the world. Up until now classic disease staging remains the main modality of predictor of prognosis and treatment options.So the need for certain easily available prognostic markers are still under search. One such indicator is by assessing the Microsatellite instability by Immunohistochemistry. AIMS AND OBJECTIVES: In this study, we evaluate the status of MLH1, MSH2, PMS2 expression in Colorectal carcinoma and the proportion of MSI-H and MSS/MSI-low tumors thereby aiding in prognosis and immunotherapy. MATERIALS AND METHODS: This is a retrospective and prospective study conducted in the Institute of Pathology-Madras Medical College, Rajiv Gandhi Government General Hospital for a period of 2 years from June 2017 - June 2019. The Hemicolectomy specimens with the clinical details of respective patient are collected. Corresponding HPE slides are prepared from formalin fixed paraffin embedded tissue of Hemicolectomy specimens. Blocks of histopathologically proven colorectal carcinomas are taken up for MLH1, MSH2, PMS2 immunohistochemical staining. RESULTS: In this study the alternative method of having 2 antibody panel of MLH 1 and MSH2 instead of the routine 4 antibody panel of MLH1, MSH2, MSH6, PMS2 can be considered as a preliminary step in identifying microsatellite instability in colorectal cancer since patients of MSI-H tumors respond well with immunotherapy. CONCLUSION This is a hospital based study and may not represent the true incidence of disease in the community. Majority of patients are over 50 years of age and there is more male preponderance. As many patients present with advanced disease the need for easily available less expensive prognostic marker is increasing and this can be accomplished by using the two antibody panel of Immunohistochemical markers MLH1 and MSH2 so that MSI-H patients can be easily identified and they can be given targeted immunotherapy to which the response is very good. Further studies are needed on the molecular characteristics of certain histologic types and it will improve our understanding of their prognostic implications and contribute to the tailored treatment.

Item Type: Thesis (Masters)
Additional Information: 201713007
Uncontrolled Keywords: Microsatellite instability, Mismatch repair, Colorectal carcinomas.
Subjects: MEDICAL > Pathology
Depositing User: Subramani R
Date Deposited: 29 Jan 2021 15:35
Last Modified: 29 Jan 2021 15:35

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