EXPRESSION PATTERN OF GASTROINTESTINAL MARKERS IN NATIVE COLORECTAL EPITHELIUM, LESIONS, AND CARCINOMAS

Three small peptides with a typical cysteine-rich domain (TFF or P-dom ain) display a specific folding structure (trefoil); they are abundant ly expressed on mucosal surfaces of normal and neoplastic gastrointest inal tissues. This epithelial location coincides with mucin secretion and, although not proven beyond doubt, this association is suggestive of their function in maintenance of surface integrity. Using normal co lon epithelium, premalignant lesions and tumor samples and specific an tibodies we studied expression of these peptides in colorectal carcino mas. RT PCR was performed to extend the sensitivity of the assays. Whi le coexpression of pS2, hITF, MUC1 and MUC2 was demonstrated, MUC5 was absent and no simultaneous activity of pS2 and SML1 (as in gastric mu cosa and carcinoma) was noted in rectal tumors. Actively transcribed a nd expressed cytokeratin 20 and GAPDH were used as experimental contro ls for immunostaining and RT-PCR, respectively.