p53 Expression in colorectal cancer: Relation to tumor type, DNA ploidy pattern, and short-term survival

p53 protein expression was evaluated in a series of 204 primary colorectal adenocarcinomas by immunohistochemistry using frozen tissue sections and monoclonal antibody DO-7. Nuclear staining of more than 5% of neoplastic cells was observed in 124 (60.8%) adenocarcinomas, which were classified as p53 positive. p53 immunoreactivity was found to be unrelated to several clinical and pathologic variables, including age and sex of patient, tumor site, tumor stage, grade of differentiation, pattern of growth, degree of peritumoral lymphocytic infiltration, and venous invasion. A strong association was demonstrated between p53 immunostaining and tumor type. Only 4 of 21 mucinous carcinomas examined (19%) were p53 positive. Conversely, 120 of 183 (65.6%) nonmucinous adenocarcinomas showed positive p53 immunostaining (P <.0001). p53 expression also was related to the flow cytometric DNA ploidy pattern, aneuploid carcinomas with DI >1.20 showing higher frequency of p53 overexpression than DNA dip...