Isobaric tags for relative and absolute quantitation analysis on serum markers of pancreatic cancer based on mass spectrometry

Abstract

Objective To determine the expression of serum proteins in pancreatic cancer patients based on mass spectrometry to screen differential proteins and to find potential molecular biomarkers to prediagnosis of pancreatic cancer. Methods The technique of isobaric tags for relative and absolute quantitation (iTRAQ) and two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) were used to analyze the serum proteins in 15 pancreatic cancer patients and 10 healthy controls. Screening for serum differential proteins was performed via retrieving Panther, Mascot and Scaffold databases. Ingenuity Pathway Analysis was used to detect the correlation between proteins. Results The expression level of 442 proteins was quantified, and 76 proteins were found to be differentially expressed which changed corresponding biological process. The up-regulation of DNA repair protein 50 (RAD50) and down-regulation of transforming growth factor β1 (TGFβ1) and apoptosis protease-activating factor 1 (APAF1) which were correlated with cell growth and apoptosis were found in pancreatic cancer. A closely interacted network was formed between these three differential proteins and other molecules, which could effect metabolism in pancreatic cancer patients. Conclusion Differential expression of serum proteins screened by iTRAQ in pancreatic cancer patients may be the potential markers of pancreatic cancer, which can provide molecular basis for early diagnosis of pancreatic cancer. Key words: Pancreatic neoplasms; Tumor markers, biological; Isobaric tags for relative and absolute quantitation; Proteomics; Serum