Epithelial blood group antigens in colon polyps. I. Morphologic distribution and relationship to differentiation.

The distribution patterns of epithelial blood group AB antigens (BG) in colon polyps of varying degrees of differentiation were studied by the mixed cell agglutination reaction. BG appeared in colon polyps if a certain degree of dedifferentiation was present. Two different distribution patterns were recognized: 1) association of BG with the secretory part of goblet cells with slight-to-moderate atypia and 2) association of BG with the whole cells in cases of pronounced dedifferentiation and loss of secretory activity. The second type resembled the distribution pattern of BG found previously in colon carcinomas. With respect to BG, the mucosa of colon polyps behaved similarly to embryonal colon mucosa. The detection of BG represents a useful method to assess objectively the degree of dedifferentiation in most colon polyps.