α1-Acid Glycoprotein with Highly Fucosylated Glycans as a Potential Diagnostic Marker for Early Detection of Hepatobiliary and Pancreatic Cancers

<b>Background</b>: Previously, we reported elevated levels of fucosylated α₁-acid glycoprotein (fAGP) in plasma samples from patients with diverse types of cancers. Accordingly, fAGP was assumed to be a potential biomarker for the early detection of cancers. <b>Methods</b>: The fAGP level was retrospectively measured in preoperative plasma samples from 213 patients with either hepatic, biliary tract, or pancreatic cancer and was analyzed together with levels of six existing tumor markers determined as reference standards. <b>Results</b>: When the cutoff value was set at 25.45 U/μg, elevated levels of fAGP were significantly observed in cancer patients. The sensitivity, specificity, and accuracy for the detection of malignancy in these diseases were determined to be 70.79, 51.72, and 68.12, respectively. In contrast, all the tumor markers exhibited low sensitivity and accuracy, even though they commonly had extremely high (≥80%) specificity. Further, a significant number of patients in both early and advanced clinical stages were found to be false negative in these tumor makers but were found to be positive in the fAGP level. A dramatic improvement in the diagnosis by tumor markers in such patients with all clinical stages was found by the determination of the fAGP level. This indicated that fAGP could serve to correct false-negative diagnosis with tumor markers. <b>Conclusions</b>: It is believed that fAGP could be a relevant, unique, and highly sensitive biomarker for early diagnosis of hepatobiliary and pancreatic cancers.