Abnormal pattern of mucus-associated M1 antigens in histologically normal mucosa adjacent to colonic adenocarcinomas.

Apparently normal mucosae adjacent to colon adenocarcinomas were studied by cutting strips of mucosa from the entire length of 120 surgical specimens (94 located on the distal colon and 26 on the proximal colon). These mucosae were coiled into "Swiss rolls." Their mucus alterations were mapped by immunoperoxidase using antibodies against M1 antigens, oncofetal markers associated with precancerous colonic mucosa. We demonstrated mucus modifications in patches of mucosa at a distance from frank tumors. The extent of these alterations was not related to invasion by the adjacent carcinoma according to Dukes' classification. However, these mucus modifications were more frequently observed on the distal than on the proximal side, were more often found adjacent to mucinous hyperplasia or adenoma, and were observed in 8 of 10 mucosae bearing metachronous or synchronous distal colonic adenocarcinomas. Our results suggest that the M1 modifications characterizing an early stage of carcinogenesis could have a putative prognostic value in estimating the risk for metachronous distal colonic adenocarcinomas.