Forssman antigen is a commonly occurring
heterophile antigen but is thought not to be present in most humans. Recent biochemical studies, however, have shown the presence of
Forssman antigen in several forms of human
cancer, including gastric, colon, and
lung cancers. Immunohistochemical staining with both monoclonal and polyclonal
antibodies has failed to demonstrate this
antigen in human tissues. In this study we conclusively demonstrated the presence of
Forssman antigen in cytoplasm of colon goblet cells, especially those in the so-called transitional mucosa adjacent to
carcinoma. Specimens from 69 of 70 patients with
colon cancer contained the
antigen in goblet cells in transitional mucosae. The
antigen was successfully demonstrated only after removal of
sialic acid by alkaline hydrolysis-
neuraminidase digestion. Localization of the
antigen was quite different from that of Tn and human
blood group A, B, and H
antigens. This
antigen was thought to be associated exclusively with globo-series
glycolipids, and its existence in
glycoproteins has not been conclusively demonstrated. However, the results presented here, based on proteolytic digestion and
lipid extraction studies, strongly suggest that the
antigen is also contained in
glycoproteins.