The value of serum GPDA-F for the diagnosis of primary hepatocellular carcinoma.

Objective To investigate the role of glycylproline dipeptidyl aminopeptidase isoenzymes in the diag- nosis of primary hepatocellular carcinoma (PHC). Methods We developed a stage gradient polyacrylamide gel electro- phoresis system to separate serum GPDA isoenzymes. Total GPDA activities, alpha-fetoprotein, the sizes of tumors and alanine aminotransferase (ALT) activities were also measured simultaneously and the correlation between GPDA-F and these indices was analyzed. Results Serum GPDA was separated into two bands, namely fast band (GPDA-F) and slow band (GPDA-S). GPDA-F was negative in all healthy persons as well as in the patients with benign liver filling defects, while it was positive in 85.3% cases of PHC. Liver cirrhosis, chronic hepatitis, extrahepatic carcinoma and metastatic liver carci- noma had low positive rates. GPDA-F was positively correlated with serum total GPDA activities, but had no correlation with AFP and size of the tumors. There was the correlation between GPDA-F and ALT in benign liver diseases, but no correlation between GPDA-F and ALT in PHC. Serial measurements of serum GPDA-F showed that GPDA-F was persistently positive in PHC but might change into negative in benign liver diseases. Dynamic determination of GPDA-F might be helpful to differentiate true positive of PHC from false positive of benign liver diseases. Conclusion GPDA-F is a new serum marker of PHC. Measurement of serum GPDA-F is of value for the diagnosis of PHC, especially for those at early stage or with negative AFP.