Expression of MLH-1, PMS-2, MSH-2, MSH-6 markers and histopathological evaluation in colorectal cancer

This retrospective study is based on medical records from the Pathology Department of SVS Medical College Hospital, Mahbubnagar.This study included 36 colorectal cancer patients who underwent resections at our institution between 2019 and 2023.Clinical features and tissue characteristics of the tumors were obtained from the hospital records.The study included 36 consecutive patients with TNM stage II (22%), stage III (53%), and stage III (13%) colorectal adenocarcinoma who had received curative surgical resection.The study comprised patients with malignant colon tumors.Benign colon tumors and inflammatory and metastatic lesions were all excluded.IHC was used to investigate mucosal samples and surgical resections of colon tumors.Microarrays and immunohistochemistry were used to investigate the expression of mismatch repair proteins such as MLH1, MSH2, MSH6, and PMS2.Two pathologists analyzed hematoxylin and eosin sections, mucinous components, polyp origins, tumor stages, lymphovascular and perineural invasions, lymphocyte densities, surgical margins, and lymph node metastases. Highlights What is current knowledge?Loss of expression of immunohistochemical markers such as MLH-1, MSH2, PMS-2, and MSH-6 was associated with poor differentiation and mucinous adenocarcinomas.There was a significant relationship between the cecum and ascending colon location and lower expression of PMS-2 & MSH-6. What is new here?The study found that low levels of MSH-2 and MSH-6 were associated with colon location, poor differentiation, and mucinous differentiation.It also found a strong link between MLH-1, MSH-2, PMS-2, and MSH-6 expressions and colorectal cancer and clinical characteristics of tumors with microsatellite instability.