Inappropriate mucin production in endodermal carcinoma--one point of view.

The mucosal lining cells in the gastrointestinal tract respond to a threatening situation by secreting mucins manufactured during foetal life and this secretion is considered to be an early manifestation of cytogenetic instability and which may be the first step in the process of malignant transformation. Using immunohistological techniques and specific antisera against SIMA (small intestinal mucin antigen), LIMA (large intestinal mucin antigen) and CEA (carcinoembryonic antigen) the presence of these mucin antigens was studied in resected specimens from colonic, gastric and gall bladder carcinomas as well as in mucinous tumours of the ovary. Inappropriate or oncofoetal mucins were present in the majority of endodermal carcinomas, in associated metaplastic epithelium and premalignant lesions such as polyps. These antigens were also demonstrated in normal histological epithelium at some distance from the tumour. These findings lead to a better understanding of the biological behaviour of preneoplastic lesions of endodermal tissues and will aid in developing sensitive diagnostic tests for the presence of these substances.