Organized differentiation of tumor cells of villous adenomas of the large intestine

The present study was undertaken to explore whether tumor cells of villous adenomas of the human colon showed an organized expression of differentiation markers. Eleven cases of villous adenomas were examined by employing histochemical techniques, which are useful for characterizing the colonic mucosa, including high iron diamine-alcian blue pH 2.5, lectin stains with DBA, GSA-I and UEA-I, immunostainings for blood group A determinant, lysozyme, and proliferating cell nuclear antigen (PCNA). The results demonstrated that the adenoma tissues showed the organized expression of these sugar moieties or antigens similar to those found in the normal colon crypts. Namely, tumor cells in the upper portions of tumor tissues revealed characteristic features of normal epithelia, lining the upper compartment of the crypts, and contained sialomucins, which possessed DBA reactivity. Tumor cells in the lower portions, on the other hand, resembled epithelia lining the lower compartments of the crypts, contained sulfomucins, showed GSA-I and UEA-I reactivities, and stained for blood group A determinant and lysozyme. PCNA-positive cells were more abundant in the lower portions of the tumor tissues than in the upper portions. It seems likely that cellular differentiation, similar to normal crypt cells, occurs in the tumor tissues.