Study of immunohistochemical expression of P53 In colorectal carcinoma

Abstract

Introduction: p53 is a very commonly mutated gene in colon cancer and the prevalence of p53 mutations in colorectal cancer varies from 40 to 60% in various studies. Molecular pathogenesis of colorectal cancer commonly involves mutation in p53 gene which leads to expression of p53 protein in tumor cells. Some studies have reported that the presence of p53 mutations in colon cancer indicates a relatively poor prognosis, while other studies have failed to show such a relationship. Observation: The present study was done to study p53 expression in colorectal carcinoma and to correlate it with various pathological factors i.e. tumor size, tumor type, grade of tumor and depth of invasion. Materials and Methods: We studied 38 cases of colorectal carcinoma (29 non mucinous adenocarcinoma and 9 mucinous adenocarcinoma). p53 expression was evaluated by immunohistochemistry. The correlation between p53 protein overexpression and each variable was evaluated using Chi-square analysis and Fisher Exact test. Results: Positive p53 immunostaining was observed in 58%. p53 expression showed an increasing trend with increasing histological grade and the difference was statistically not significant. p53 overexpression was related to the depth of tumor invasion which was maximum in stage pT4 followed by stage pT3 and stage pT2 and the difference was statistically significant (p value = 0.032). No significant correlation was found between p53 expression and size, type and grade of tumor in colorectal carcinoma. Keywords: p53, Colorectal carcinoma, Immunohistochemistry.