Pancreatic juice is an excellent source for the identification of protein biomarkers of pancreatic cancer. To systematically study the pancreatic cancer proteome in pancreatic juice, we used isotope-code affinity tag and tandem mass spectrometry (MS/MS) to perform comprehensive quantitative protein profiling of the pancreatic juice from pancreatic cancer patients and normal controls. Isotope-code affinity tag coupled with MS/MS allows the systematic study of the proteome and measures the protein abundance in pancreatic juice–with the potential for development of biomarkers. A total of 105 proteins were identified and quantified in the pancreatic juice from pancreatic cancer patient, of which 30 proteins showed abundance changes of at least two-fold in pancreatic cancer juice compared to normal controls. Many of these proteins have been externally validated. This is the first comprehensive study of the pancreatic juice proteome by quantitative global protein profiling, and it revealed numerous proteins that are newly discovered to be associated with pancreatic cancer, providing candidates for diagnostic biomarkers. One of the identified proteins, IGFBP-2 (insulin-like growth factor binding protein-2) was further validated by western blotting to be elevated in pancreatic cancer juice and over-expressed in pancreatic cancer tissue.

[Proc Amer Assoc Cancer Res, Volume 47, 2006]