Abstract

Carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA were traced by paired immunofluorescence staining in 102 large bowel carcinomas from 99 patients. The immunohistochemical results were evaluated semiquantitatively in relation to histological tumour grade, clinicopathological stage, and preoperative plasma CEA concentration. CEA expression was significantly increased (p less than 0.05) in the following order: histologically normal colon mucosa, transitional mucosa adjacent to tumours, neoplastic epithelium; the reverse was true for the expression of SC and epithelial IgA (p less than 0.01). CEA was significantly more abundant in the moderately and poorly differentiated tumors than in the well differentiated ones (p less than 0.05), whereas the latter showed better expression of SC (p less than 0.05) and epithelial IgA (p approximately 0.06). In the transitional mucosa, CEA staining tended to be inversely related to histological tumour grade, whereas SC and epithelial IgA were significantly better seen in this zone when the adjacent tumour was well differentiated than when it was moderately or poorly differentiated (p less than 0.01). Furthermore, the expression of SC and epithelial IgA in the transitional mucosa decreased with increasing invasiveness of the tumours, whereas the opposite relation was indicated for CEA expression. Plasma CEA concentrations were not clearly correlated with histological levels than the localised well differentiated tumours tended to be associated with lower levels than the localised moderately differentiated ones (p approximately 0.06). Moreover, the latter variety was associated with lower plasma CEA concentrations than disseminated tumours of comparable differentiation (p less than 0.01).