Screening for serological biomarkers of pancreatic cancer by two-dimensional electrophoresis and liquid chromatography-tandem mass spectrometry.

Pancreatic cancer (PC) is one of the most lethal malignant tumors because of late diagnosis and the lack of response to various therapies. To identify potential biomarkers in cancerous serum from early stage PC patients, we carried out two-dimensional gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to compare the serum proteomic profiles from 45 patients with PC and 20 healthy volunteers. Seven spots showed differential expression on 2-DE gels and two up-regulated protein spots were identified by LC-MS/MS as α-1-antitrypsin (AAT). These protein spots were also confirmed by Western blotting. This is the first time that AAT isoforms have been identified as potential serum biomarkers for PC. The serum isoforms of AAT may be clinically useful for PC diagnosis and monitoring.