Screening of differentially expressed proteins from human esophageal cancer and esophageal tissues by two-dimensional difference gel electrophoresis and mass spectrometry

Objective: To establish two-dimensional electrophoresis profiles from human esophageal cancer tissue and paired normal esophageal tissue and identify differentially expressed proteins to identify the molecular markers for early-stage diagnosis.

Methods: The total proteins of human esophageal cancer tissue and paired normal esophageal tissue were separated by immobilized pH gradient-based two-dimensional gel electrophoresis (2-DE). The 6 differentially expressed proteins were analyzed by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). The peptide mass fingerprintings (PMF) were identified by database searching. Six differentially expressed proteins were validated by RT-PCR.

Results: The well-resolved, reproducible 2-DE patterns of esophageal cancer tissue and esophageal normal tissue were established. Using MALDI-TOF-MS technology, 6 differential protein spots were identified. Among them, the expressions of squamous cell carcinoma antigen 1 (SCCA1b), KRT4 and annexin A1 were downregulated and triosephosphate isomerase (TPI1), heat shock protein 27 (HSP27) and manganese superoxide dismutase (MnSOD) were upregulated in esophageal cancer tissues.

Conclusions: The identification of differential expressed proteins in human esophageal cancer and normal tissue will be helpful for screening the biomarker for early-stage diagnosis.