Clinical application of a lectin-antibody ELISA to measure fucosylated haptoglobin in sera of patients with pancreatic cancer

Background: Recent advanced techniques in glycobiology have produced a number of tumor marker candidates. As a result from the glycomic approach, we found that fucosylated haptoglobin in sera was a possible tumor marker for pancreatic cancer (PC). Although Aleuria aurantia lectin (AAL) blotting can detect fucosylated haptoglobin, it is difficult to quantify fucosylated haptoglobin precisely. To overcome this problem, we developed a fucosylated haptoglobin detection kit as a sandwich enzyme-linked immune sorbent assay (ELISA) using AAL and the Fab portion of anti-haptoglobin antibody. In the present study, we investigated the clinical application of this lectin-antibody ELISA kit to measure fucosylated haptoglobin in PC. Methods: We measured fucosylated haptoglobin in patients with PC with a lectin-antibody ELISA kit. The fucosylated haptoglobin measured with this assay was compared with lectin blotting data, and the discrepancy was analyzed by immunoprecipitation methods. The concentration of fucosylated haptoglobin was investigated with respect to the clinical stage of PC. We also measured fucosylated haptoglobin, using 397 cases of several types of cancers including PC, benign diseases, and normal controls. Results: The sensitivity and specificity for the differential diagnosis of PC from normal controls was 50% and 91%, respectively. The results from lectin-antibody ELISA were significantly correlated with data from previous AAL blotting studies. Positive rates of fucosylated haptoglobin with this method in patients with PC were significantly higher in cases of stage IV compared with other clinical stages. Fucosylated haptoglobin was increased in several types of cancers, in which fucosylated haptoglobin was reported to increase. Conclusions: While certain cases showed a discrepancy in fucosylated haptoglobin concentrations between the lectin-antibody ELISA and conventional lectin blotting, this novel type of lectin-antibody ELISA might be useful for a tumor marker for PC. Clin Chem Lab Med 2010;48:505-12.