Immunohistochemical study of secretory component, secretory IgA and carcinoembryonic antigen in large bowel carcinomas

The epithelium of 41 large bowel carcinomas was scored immunohistochemically on a semiquantitative basis for the presence of secretory component (SC), secretory IgA, and carcinoembryonic antigen (CEA). Both the tumour and the adjacent "transitional mucosa" were evaluated. The various immunofluorescence scores obtained, the histological grades of the tumours, their Dukes' stages, and the plasma CEA levels were subjected to non-parametric correlation analyses. Tumour SC was positively correlated with histological tumour grade and inversely related to Dukes' stage. Tumour secretory IgA generally showed a pattern similar to that of SC. Tumour CEA showed no correlation with any of the other parameters. The contents of SC and secretory IgA in the transitional mucosa were negatively correlated with Dukes' stage and plasma CEA. Whether the variations observed in the epithelial cell markers reflected primary events in the malignant development or secondary alterations is unknown. Nevertheless, especially the amount of tumour SC may turn out to be of prognostic value.