Hedström J, Haglund C, Kemppainen E, Leinimaa M, Leinonen J, Stenman UH. Time-resolved immunofluorometric assay of trypsin-1 complexed with alpha(1)-antitrypsin in serum: increased immunoreactivity in patients with biliary tract cancer.
Clin Chem 1999;
45:1768-73. [PMID:
10508123]
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Abstract
BACKGROUND
Increased serum concentrations of trypsin immunoreactivity occur in patients with biliary tract cancer. To characterize this trypsin, we developed a sensitive time-resolved immunofluorometric assay for trypsin-1 complexed with alpha(1)-antitrypsin (AAT) and studied the concentrations of this complex in sera from healthy individuals (n = 130) and patients with benign biliary disease (n = 32), biliary tract cancer (n = 17), pancreatic cancer (n = 27), and hepatocellular cancer (n = 12).
METHODS
We used a trypsin-1-specific monoclonal antibody on the solid phase and a europium-labeled polyclonal antibody to AAT as tracer. The detection limit was 0.42 microgram/L. The validity of the trypsin-1-AAT test for detection of biliary tract cancer was compared with trypsin-2-AAT and CA19-9.
RESULTS
Increased concentrations of trypsin-1-AAT (>33 microgram/L) were found in 76% of patients with biliary tract cancer, and the concentrations were significantly higher than in those with benign biliary disease (P <0. 0001). The median concentration of trypsin-1-AAT in serum from patients with biliary tract cancer was 3.7-fold higher than in healthy controls, 2.6-fold higher than in patients with benign biliary tract disease, 1.7-fold higher than in patients with pancreatic cancer, and 2.0-fold higher than in patients with hepatocellular cancer.
CONCLUSIONS
Of the markers studied, trypsin-1-AAT had the largest area (0.83) under the receiver operating curve in differentiating biliary tract cancer from benign biliary tract disease. Our results suggest that trypsin-1-AAT is a new potential marker for biliary tract cancer.
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