Expression of carcinoembryonic antigen, T-antigen, and oncogene products as markers of neoplastic and preneoplastic colonic mucosa.

Several crypt abnormalities have been demonstrated in the mucosa of neoplastic and preneoplastic lesions of the large intestine. In addition, certain tumor markers are expressed in large intestinal carcinoma but not in normal mucosa. To determine whether any correlation exists between tumor marker expression and crypt abnormalities and at what stage markers are expressed, we studied specimens of large intestinal mucosa from 13 patients with preneoplastic conditions (adenomatous polyp, familial polyposis, Crohn's disease, and ulcerative colitis). The tumor markers examined include carcinoembryonic antigen (CEA), the ras gene products p21 and p21ser (mutated form), and beta-D-galactosyl-(1----3)-alpha-N-acetyl-D-galactosamine (gal--gal NAc, also known as T-antigen). Results were compared to those of five cases of adenocarcinoma of colon and three control cases of colonic mucosa obtained at immediate autopsy. All four markers were expressed in three of the five cases of adenocarcinoma, but none were expressed in the control cases. Variable expression of each marker was demonstrated in the dilated, distorted crypts of preneoplastic lesions. CEA and gal--gal NAc appeared to be expressed most frequently, suggesting that these are common markers or are expressed at an earlier stage in the neoplastic process than p21 or p21ser. Demonstration of such markers in preneoplastic conditions may be of use in determining the malignant potential and in monitoring these lesions.