Comparative proteomics analysis of colorectal cancer.

BACKGROUND AND OBJECTIVE Protein expression in colon and rectal cancer (CRC) and paired normal tissues was examined by two-dimensional gel electrophoresis (2-DE) to identify differentially expressed proteins. MATERIALS AND METHODS Five fresh colorectal cancer and paired adjacent normal tissues were obtained and differentially expressed protein spots were determined using PDQuest software, with identification on the basis of MALDI- TOF mass spectra. RESULTS Compared with normal colorectal mucosa, protein abnormal expression of 65 spots varying more than 1.5 times were found in 2-DE gels from colorectal cancer samples (P<0.05); forty-two proteins were up-regulated and 23 were down-regulated; twelve protein spots were identified using mass spectrometry, of which 8 were up-regulated, including HSPB1 and Annexin A4, while 4 were down-regulated, the results being consistent with Western blot findings. CONCLUSIONS Two-dimensional electrophoresis reference maps for CRC tissues and adjacent normal mucosa (NMC) were established and 12 differentially expressed proteins were identified. Up-regulated HSPB1 and Annexin A4 may play many important roles in the pathogenesis of colorectal cancer.