P53 IMMUNOREACTIVE STAIN AND EARLY COLORECTAL ADENOCARCINOMAS

565 cases of early colorectal adenocarcinomas were used in this study to examine mechanisms of carcinogenesis. Specimens were paraffin embed ded and histological sections were stained with haematoxylin-eosin and p53. Macroscopically, early colorectal adenocarcinomas could be class ified into two types: protruding and depressed. The former were compos ed of branching glands, while the latter were composed of straight gla nds which opened to the surface. The p53 positive ratio was similar fo r protruding tumours but was higher in depressed submucosal invasive a denocarcinomas than in depressed intramucosal adenocarcinomas. These r esults raise the possibility of at least two pathways for colorectal c arcinogenesis, adenoma-carcinoma lesions and de novo carcinoma lesions .