Immunohistochemical Expression of MSH6 and MSH2 in Colorectal Cancer

Colorectal cancer (CRC) is the cancer of the colon and rectum, which are situated, in the lower digestive tract. CRC is caused by mutations that target oncogenes, tumor suppressor genes and genes related to DNA repair mechanisms. The aim of this study was to observe and study the expression of MSH6 and MSH2 in colorectal cancer and to determine the expression of these markers in normal colorectal sample, colorectal intraepithelial neoplasia and colorectal cancer. A total of 65 formalin fixed paraffin embedded tissue blocks comprising 15 normal colorectal tissues, 25 colonic polyps tissues and 25 malignant invasive colorectal cancer were retrieved from the Pathological Archives. Immunohistochemical analysis was carried out on the samples. The immunohistochemical staining was evaluated and the results obtained were considered. Nuclear MSH2 staining was expressed; Normal cases showed a positivity rate of 46%, Colonic polyps’ cases showed a positivity rate of 56%, colorectal carcinoma cases had a positivity rate of 100% as all of the cells showed significant expression. Nuclear MSH6 was expressed; Normal cases showed a positivity rate of 40%, Colonic polyps’ cases showed a positivity rate of 60%, colorectal carcinoma cases had a positivity rate of 100% as all of the cells showed significant expression. There was a distinct upregulation of MSH2 and MSH6. The upregulated expression of MSH2 and MSH6 in normal colorectal tissues, neoplastic colonic polyps and colorectal cancer confirms the usefulness of tumor biomarkers and Immunohistochemistry in predicting progression of malignant lesions.