Plasma proteomic analysis of pancreatic cancer by 2-dimensional gel electrophoresis

Objective: Late diagnosis is the major reason for poor prognosis of pancreatic cancer (PC). Developing new biomarkers of early stage detection is critical. Methods: Proteomic analysis with 2-dimensional gel electrophoresis was used to identify differentially expressed proteins in plasma of PC patients. The 2-dimensional gel electrophoresis plasma protein profiles of 11 PC patients (preoperative and postoperative) were compared with those of 10 patients with chronic pancreatitis (CP) and 11 healthy controls. Results: Five proteins were found to be constantly changed. Haptoglobin (Hp) (3 chain and leucine-rich alpha(2) glycoprotein upregulated slightly in PC plasma. Pancreatic cancer had a higher frequency of Hp2-2 phenotype but lacked Hp1-1 phenotype. Hemoglobin was increased significantly in plasma samples of PC and CP. alpha(1) Antitrypsin gradually increased its expression level in healthy control, PC, and CP. Immunoglobin J chain was elevated in CP plasma samples. Haptoglobin, al antitrypsin, and leucine-rich alpha(2)-glycoprotein were all greatly elevated after tumor resection in PC patients. Conclusions: Proteomic analysis can simultaneously detect changes of multiproteins in plasma of PC, but detected proteins are abundant and common plasma proteins and their diagnostic value may be limited.