p53 protein in colorectal cancer: Clinicopathological correlation and prognosis significance

The occurrence of p53 overexpression was studied in 40 colorectal carcinomas in order to determine whether it is related to established prognostic indicators and/or patient survival. By using immunohistochemistry, p53 overexpression was found in 55% of tumours with a higher frequency in left-sided tumours (62%) than right-sided ones (43%). The G2 and Dukes B carcinomas showed a higher risk for p53 overexpression than G3 and Dukes C ones. No correlation was found between p53 immunostaining and age, sex, and DNA ploidy. No difference was found in disease-free and overall survival between p53+ and p53- tumours by using both the univariate (log-rank test) and multivariate (Cox regression model) analyses. Our data show that the immunohistochemical overexpression of p53 does not predict the survival in patients with colorectal carcinoma and that genetic alterations of p53 disappear during the late stages of tumoral growth and invasion because of the entropy of a well-radicated malignant tumour. Therefore, we suggest to limit the p53 immunohistochemistry as an inexpensive and reliable method to routine clinical application to identify the early steps of colorectal carcinogenesis.