Glycoprotein Biomarker Panel for Pancreatic Cancer Discovered by Quantitative Proteomics Analysis

Pancreatic
cancer is a lethal disease where specific early detection
biomarkers would be very valuable to improve outcomes in patients.
Many previous studies have compared biosamples from pancreatic cancer
patients with healthy controls to find potential biomarkers. However,
a range of related disease conditions can influence the performance
of these putative biomarkers, including pancreatitis and diabetes.
In this study, quantitative proteomics methods were applied to discover
potential serum glycoprotein biomarkers that distinguish pancreatic
cancer from other pancreas related conditions (diabetes, cyst, chronic
pancreatitis, obstructive jaundice) and healthy controls. Aleuria aurantia lectin (AAL) was used to extract
fucosylated glycoproteins and then both TMT protein-level labeling
and label-free quantitative analysis were performed to analyze glycoprotein
differences from 179 serum samples across the six different conditions.
A total of 243 and 354 serum proteins were identified and quantified
by label-free and TMT protein-level quantitative strategies, respectively.
Nineteen and 25 proteins were found to show significant differences
in samples between the pancreatic cancer and other conditions using
the label-free and TMT strategies, respectively, with 7 proteins considered
significant in both methods. Significantly different glycoproteins
were further validated by lectin-ELISA and ELISA assays. Four candidates
were identified as potential markers with profiles found to be highly
complementary with CA 19–9 (p < 0.001).
Obstructive jaundice (OJ) was found to have a significant impact on
the performance of every marker protein, including CA 19–9.
The combination of α-1-antichymotrypsin (AACT), thrombospondin-1
(THBS1), and haptoglobin (HPT) outperformed CA 19–9 in distinguishing
pancreatic cancer from normal controls (AUC = 0.95), diabetes (AUC
= 0.89), cyst (AUC = 0.82), and chronic pancreatitis (AUC = 0.90).
A marker panel of AACT, THBS1, HPT, and CA 19–9 showed a high
diagnostic potential in distinguishing pancreatic cancer from other
conditions with OJ (AUC = 0.92) or without OJ (AUC = 0.95).