THE RELATIONSHIP BETWEEN ANEUPLOIDY AND P53 OVEREXPRESSION DURING GENESIS OF COLORECTAL ADENOCARCINOMA

This paper describes the investigation of nuclear DNA content and p53 immunoreactivity in normal mucosa (n = 25), mildly (n = 15), moderatel y (n = 28) and severely atypical (n = 22) colorectal adenomas and in c olorectal adenocarcinomas (n = 116). Twenty-seven per cent of the mild ly atypical, 43% of the moderately, 77% of the severely atypical adeno mas and 91% of the colorectal carcinomas were distinctly aneuploid. In the aneuploid lesions p53 immunoreactivity was not observed in mildly atypical adenomas, whereas 17% of the moderately atypical, 24% of the severely atypical adenomas and 66% of the adenocarcinomas were p53 po sitive. None of the diploid lesions were p53 immunoreactive. These dat a are interpreted to indicate that genomic instability as reflected by crude aneuploidy occurs early during genesis of colorectal carcinoma and represents a high risk factor for p53-gene mutation.