title: Glycylproline dipeptidyl aminopeptidase isoenzyme in diagnosis of primary hepatocellular carcinoma.
abstract: OBJECTIVE
  To investigate the role of glycylproline dipeptidyl aminopeptidase (GPDA) isoenzyme in the diagnosis of primary hepatocellular carcinoma (PHC), especially in patients with negative alpha-fetoprotein (AFP).
  
  
  METHODS
  A stage gradient polyacrylamide gel discontinuous electrophoresis system was developed to separate serum GPDA isoenzymes, which were determined in 102 patients with PHC, 45 cases with liver cirrhosis, 24 cases with chronic hepatitis, 35 cases with benign liver space-occupying lesions, 20 cases with metastatic liver cancer and 50 cases with extra-hepatic cancer, as well as 80 healthy subjects. The relationships between GPDA isoenzymes and AFP, the sizes of tumors, as well as alanine aminotransferase (ALT) were also analyzed.
  
  
  RESULTS
  Serum GPDA was separated into two isoenzymes, GPDA-S and GPDA-F. The former was positive in all subjects, while the latter was found mainly in majority of PHC (85.3 %) and a few cases with liver cirrhosis (11.1 %), chronic hepatitis (33.3 %), metastatic liver cancer (15.0 %) and non-hepatic cancer (16.0 %). GPDA-F was negative in all healthy subjects and patients with benign liver space-occupying lesions, including abscess, cysts and angioma. There was no correlation between GPDA-F and AFP concentration or tumor size. GPDA-F was consistently positive and not correlated with ALT in PHC, but GPDA-F often converted to negative as decline of ALT in benign liver diseases. The electrophoretic migration of GPDA-F became sluggish after the treatment of neuraminidase.
  
  
  CONCLUSIONS
  GPDA-F is a new useful serum marker for PHC. Measurement of serum GPDA-F is helpful in diagnosis of PHC, especially in patients with negative AFP. GPDA-F is one kind of glycoproteins rich in sialic acid.
authors.affiliation: Department of Gastroenterology, Affiliated Hospital of Nantong Medical College, Nantong 226001, Jiangsu Province, China. nirz@public.nt.js.cn
authors.forename: Run-Zhou
authors.initials: RZ
authors.lastname: Ni
authors.forename: Jie-Fei
authors.initials: JF
authors.lastname: Huang
authors.forename: Ming-Bing
authors.initials: MB
authors.lastname: Xiao
authors.forename: Mei
authors.initials: M
authors.lastname: Li
authors.forename: Xian-Yong
authors.initials: XY
authors.lastname: Meng
mesh_terms: D000626:Aminopeptidases / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D008107:Liver Diseases / Q000097:blood / Q000201:enzymology; D008113:Liver Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D009369:Neoplasms / Q000097:blood / Q000145:classification; D009439:Neuraminidase; D012016:Reference Values; D015203:Reproducibility of Results; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D007527:Isoenzymes; D000509:alpha-Fetoproteins; D009439:Neuraminidase; D000626:Aminopeptidases; C018085:glycylproline dipeptidyl aminopeptidase