HIGHLY ENHANCED FUCOSYLATION OF ALPHA-FETOPROTEIN IN PATIENTS WITH GERM-CELL TUMOR

Background. We have recently reported that simultaneous determination of the fucosylation and glucosaminylation of alpha-fetoprotein (AFP) w as useful in the differential diagnosis of various liver diseases. Her e, we measured these indices in germ cell tumor and compared them with those in various diseases to reveal the characteristic feature of the carbohydrate moiety of AFP in this tumor. Methods. Fucosylation and g lucosaminylation indices of AFP were determined for 743 serum samples from 10 patients with germ cell tumor, 437 with hepatocellular carcino ma (HCC), 241 with benign liver diseases (24 patients with acute viral hepatitis, 99 with chronic hepatitis, and 118 with hepatic cirrhosis) , and 55 with carcinoma metastatic to the liver from digestive organs (41 from stomach, 10 from gallbladder, 2 from pancreas, and 2 from col on) by crossed immunoaffinoelectrophesis in the presence of concanaval in A and Lens culinaris agglutinin. Results. The fucosylation index of AFP in germ cell tumors (99% +/- 2%, mean +/- SD) was higher than tho se in HCC (39% +/- 31%), carcinoma metastatic to the liver (76% +/- 27 %), and benign liver diseases (4% +/- 7%); the differences were statis tically significant (P < 0.001). The glucosaminylation index of AFP in germ cell tumor (45% +/- 20%) also was significantly higher than thos e in HCC (4% +/- 4%) and in benign liver diseases (1% +/- 4%) (P < 0.0 01). The difference in mean percentage of the glucosaminylation index, however, was not significant between germ cell tumors (45% +/- 20%) a nd carcinoma metastatic to the liver (39% +/- 23%). Conclusions. The c urrent study indicates that the most characteristic feature of glycosy lation of AFP in germ cell tumors is fucosylation rather than glucosam inylation.