Correlation of p53 Overexpression with the Clinicopathological Prognostic Factors in Colorectal Adenocarcinoma.

Abstract

Mutation in p53 gene and accumulation of p53 protein is a common genetic event in colorectal carcinomas. p53 mutation can be detected by various techniques such as DNA sequencing, polymerase chain reaction and immunohistochemistry (IHC). However, IHC is simple and is consistent with other techniques. To establish a correlation between overexpression of p53 with the clinical features, tumour histopathology and stage of Colorectal Carcinoma (CRC). This prospective and retrospective study of clinical, histopathological and IHC features of CRC was conducted on colectomy and abdomino-perineal resection specimens received from January 2008 to June 2013. For each case, the clinical features, tumour morphology and p53 status (by IHC) were evaluated. The most common histologic type of CRC was Non-Specific Type (NST) and grade II tumours were seen predominantly (60%). Overall, 67.5% of CRCs showed p53 positivity on IHC. Intense p53 positivity was observed in 37.5% of CRCs of NST type and 33.3% of mucinous adenocarcinomas showed moderate positivity. Grade III tumours showed variable p53 positivity and those with lymph node metastasis showed moderate (55.6%) or intense positivity (53.8%). But there was no statistically significant correlation of p53 status and various clinicopathological prognostic factors. As p53 protein overexpression is seen in a relatively high percentage of CRCs, it seems that p53 mutation plays an important role in development of CRC. However, no direct correlation could be established between p53 results and the patients' age, sex, tumour site, size, histological type, grade, lymph node status, or TNM stage. A prolonged follow up is necessary to conclude whether p53 status has any influence on the long, term prognosis and patient survival.