F1-ALPHA - A NOVEL MUCIN ANTIGEN ASSOCIATED WITH GASTRIC CARCINOGENESIS

In a previous study, we obtained a novel monoclonal antibody (F1 alpha -75) directed against a synthetic mucin antigen termed F1 alpha, and d emonstrated that this antigen was expressed in a high percentage (80.2 %; 89/111) of gastric carcinomas;In the present study, we compared the expression of F1 alpha with that of sialyl-Tn antigen, a mucin antige n similar to F1 alpha, in 54 human early gastric carcinomas,intestinal metaplasia and adenomatous polyps of the stomach to determine how dif ferences in the expression of these antigens correlated with gastric c arcinogenesis. The rate of expression of F1 alpha in early gastric car cinoma tissues, 81.5%, was higher than that of sialyl-Tn antigen, 57.4 %, No correlation was found between the rate of expression and histolo gical type, depth of cancerous invasion or lymph node metastasis, Sial yl-Tn antigen was extensively expressed in 77.5% of specimens of compl ete intestinal metaplasia and in 78.6% of those of incomplete intestin al metaplasia; however, the expression of F1 alpha in those specimens was rare and sporadic, with rates of only 25.0 and 27.7%, respectively , In adenomatous polyps, the rate of expression of F1 alpha is 6.25% a nd that of sialyl-Tn antigen is 43.8%. Our findings indicate that F1 a lpha is a more specific antigen for gastric cancer than sialyl-Tn anti gen, and that F1 alpha is an antigen associated with carcinogenesis of the stomach.