A Comparative Survey on the Expression of Retinoblastoma Protein as A Tumor Suppressor Protein in Cancerous and Non-Cancerous Colorectal Tissue Samples Using Immunohistochemistry Method

Colorectal cancer is one of the most prevalent gastrointestinal malignancies. Expression of some proteins including P53, P21, E-cadherin and β-catenin is assumed to have a prognostic role for this malignancy. In the present study we evaluated the association of retinoblastoma (RB) protein expression and pathogenesis of colorectal cancer. The presence of RB in cancerous and non-cancerous colorectal tissue samples were compared using immunohistochemistry method. Tissue sections were taken from tumoral and non-tumoral defined areas of 50 colorectal cancer patients. After coloration according to immunohistochemistry method, all samples were studied for RB expression. We found RB expression in colorectal tumoral cells to be significantly higher than that of non-tumoral cells (P < 0.0001). RB overexpression in cancerous cells may lead to insensibility to apoptosis and consequent long life of affected cells as well as resistance to treatment.