Late diagnosis is the major reason for poor prognosis of pancreatic cancer (PC). Developing new biomarkers of early stage detection is critical.
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.
Five proteins were found to be constantly changed. Haptoglobin (Hp) β chain and leucine-rich α2 glycoprotein up-regulated 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. α1 Antitrypsin gradually increased its expression level in healthy control, PC, and CP. Immunoglobin J chain was elevated in CP plasma samples. Haptoglobin, α1 antitrypsin, and leucine-rich α2-glycoprotein were all greatly elevated after tumor resection in PC patients.
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.
Abbreviations: 2-DE - 2-dimensional gel electrophoresis, α1-AT - α1 antitrypsin, CP - chronic pancreatitis, Hb - hemoglobin, Hp - haptoglobin, Ig - immunoglobulin, LRG - leucine-rich α2-glycoprotein, MS - mass spectrometry, PC - pancreatic cancer, SELDI-TOF - surface-enhanced laser desorption ionization time- of-flight, sIgA - secretory immumoglobin A