血清甘氨酰脯氨酸二肽氨基肽酶同工酶对原发性肝癌的诊断价值

目的研究血清甘氨酰脯氨酸二肽氨基肽酶（grycylprolinedipeptidylaminopeptidase，GPDA）同工酶对PHC的诊断价值，提高早期PHC和AFP阴性PHC诊断水平。方法采用阶段梯度垂直平板聚丙烯酰胺凝胶电泳法进行血清GPDA同工酶分离检测，同步测定比较PHC患者血清GPDA同工酶与GPDA总活性（TGPDA）、AFP、肿瘤大小及ALT的关系。结果血清GPDA按其泳动速度可分为快带（GPDA-F）与慢带（GPDA-S）两种同工酶。PHC患者血清GPDA-F的阳性率为85.3%，而肝外肿瘤、转移性肝癌、肝炎后肝硬化、慢性肝炎中阳性率均较低，正常对照组以及良性肝占位全部阴性。GPDA-F阳性率在TGPDA活性增高组明显高于正常组（94.4%对75.0%），GPDA-F与AFP及肿瘤大小无关系。良性肝病ALT升高组GPDA-F阳性率高于ALT正常组,而PHC患者GPDA-F与ALT无关。PHC患者GPDA-F呈持续阳性，良性肝病患者GPDA-F常为一过性阳性。结论GPDA-F为一新的PHC血清标志物，有助于PHC的定性诊断，尤其对早期PHC及AFP阴性PHC的诊断具有重要价值。

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

OBJECTIVE: To investigate the role of glycylproline dipeptidyl aminopeptidase isoenzymes in the diagnosis of primary hepatocellular carcinoma (PHC). METHODS: We developed a stage gradient polyacrylamide gel electrophoresis 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 carcinoma 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.