Electrophoretic behavior and partial characterization of disease-associated serum forms of gamma-glutamyltransferase

Evaluation of the albumin-gamma-glutamyltransferase isoenzyme as a diagnostic marker of hepatocellular carcinoma-complicating liver cirrhosis

AIM

The present study aimed to evaluate the usefulness of albumin-gamma-glutamyltransferase isoenzyme in the diagnosis of hepatocellular carcinoma.

METHODS

Electrophoretic assays of gamma-glutamyltransferase isoenzymes were performed on sera from 190 cirrhotics with (n = 131) or without (n = 59) hepatocellular carcinoma, 36 patients with chronic active hepatitis, 17 patients with liver metastases, and 16 control subjects. In the group of cirrhotic patients, the serum level of alpha-fetoprotein was also assessed.

RESULTS

Albumin-gamma-glutamyltransferase was found in 88 of 131 cirrhotics with hepatocellular carcinoma, 14 of 59 cirrhotics without hepatocellular carcinoma, nine of 17 patients with liver metastases, and in none of the chronic active hepatitis or control patients. Within the cirrhotic subgroup, albumin-gamma-glutamyltransferase was effective in detecting hepatocellular carcinoma in general (sensitivity: 67%; specificity: 76%; diagnostic accuracy: 70%), and small hepatocellular carcinoma (< 3 cm; corresponding figures: 58, 76, and 69%). The best alpha-fetoprotein value discriminating between hepatocellular carcinoma and non-hepatocellular carcinoma cirrhotics was 20 ng/mL (sensitivity: 54%; specificity 85%; accuracy: 64%). The combined use of albumin-gamma-glutamyltransferase and alpha-fetoprotein, > 20 ng/mL, was associated with greater sensitivity and accuracy (84 and 74%, respectively) than those observed with either of the two markers considered alone.

CONCLUSIONS

Albumin-gamma-glutamyltransferase appears to be a sensitive diagnostic marker of both advanced and small hepatocellular carcinoma-complicating liver cirrhosis.

Multivariate discriminant analysis of biochemical parameters for the differentiation of clinically confounding liver diseases

We describe a series of studies on the contribution of laboratory medicine to the differential diagnosis of clinically confounding diseases in the field of chronic hepatobiliary diseases. Ascitic cholesterol and lactate dehydrogenase (LD), selected by multivariate discriminant analysis (MDA) from a multitude of serum and ascitic analytes, correctly classified 100% of patients with malignant ascites or non-malignant ascites. In addition, ascitic pseudouridine differentiated hepatocarcinoma (HC) from cirrhotic ascites with a diagnostic effectiveness (overall discrimination power) of 90%. A panel of analytes constituted by serum gamma-glutamyltransferase (GGT), the GGT isoenzyme complexed with low- and very low-density lipoprotein, aspartate aminotransferase, copper, hepatic alkaline phosphatase (AP), the LD-5 isoenzyme and alpha-fetoprotein (AFP), selected by the MDA, correctly classified 93% of about 200 cases of cirrhosis or HC. Finally, MDA also identified an equation, based on serum values of the LD-4/LD-5 and carcinoembryonic antigen/AFP ratios, AP and iron that correctly classified 96% of HC or secondary liver neoplasia cases in 100 patients. This approach based on panels of analytes selected by a sophisticated statistical analysis is a rapid and non-invasive contribution to the differential diagnosis of chronic liver disease including neoplasia.

Serum type-2 macro-creatine kinase isoenzyme is not a useful marker of severe liver diseases or neoplasia

We studied the creatine kinase (CK) isoenzyme pattern in sera from 332 patients affected by hepatic cirrhosis and several neoplastic diseases (102 cirrhosis, 36 hepatocarcinoma, 16 metastatic liver tumor, 40 breast cancer, 18 other neoplastic diseases and 120 cases of leukemia or lymphoma) to evaluate both its diagnostic utility for cancer diagnosis and its power as a prognostic index. Type-2 macro CK (mitochondrial creatine kinase) was detected, with no statistical difference in cirrhosis (14%), hepatocarcinoma (16%), metastatic liver tumor (31%), breast cancer (5%) and other tumors (6%). It was not detected in any patient with leukemia or lymphoma. The presence of type-2 macro CK was unrelated to the stage of either cirrhosis or hepatocarcinoma, according to Child and Okuda, respectively, nor was it correlated to serum cytolytic enzyme levels or to gamma-globulin levels. In cirrhotics, type-2 macro CK was not linked to serum levels of the following tumor markers: alpha-fetoprotein, pseudouridine and gamma-glutamyltransferase isoenzymes complexed to low-density lipoprotein. In addition, the atypical band persisted in several patients with cirrhosis monitored for six months who did not show any evidence of evolution toward hepatocarcinoma. Thus, type-2 macro CK has poor diagnostic sensitivity for neoplastic diseases, and lacks prognostic value both in cirrhosis and neoplastic diseases.