The gamma-glutamyltransferase isoenzyme pattern in serum as a signal discriminating between hepatobiliary diseases, including neoplasias.

We have used the gamma-glutamyltransferase (GGT) isoenzyme pattern in serum as a means for discriminating between hepatobiliary diseases, including neoplasias. The reference pattern, determined in 142 normal subjects with a simplified conventional cellulose acetate electrophoretic procedure, contained two GGT bands, alpha1-GGT and alpha2-GGT, in proportions of 60-80% and 20-40%, respectively. Sera from 95 hepatobiliary patients showed typical isoenzyme features: (a) a beta-migrating GGT form that was < 10% of the total GGT in chronic hepatitis and cirrhosis, and ≤ 30% of the total GGT in cirrhosis with intrahepatic cholestasis and in cases of extra- and intrahepatic obstructive jaundice, including liver neoplasias; (b) a gamma-migrating GGT band and (or) a 'dep-GGT' (nonmigrating) band in cases of extrahepatic jaundice; and (c) an albumin-migrating GGT band that had a diagnostic sensitivity of 75% for hepatic tumors. The diagnostic specificity of this last band is 92% toward other hepatic disorders and 91% toward nonhepatic neoplasias; we consider it a potential specific marker for primary or metastatic liver neoplasias.