Background and Objective: Protein expression in colon and rectal cancer (CRC) and paired normal tissues wasexamined by two-dimensional gel electrophoresis (2-DE) to identify differentially expressed proteins. Materialsand Methods: Five fresh colorectal cancer and paired adjacent normal tissues were obtained and differentiallyexpressed protein spots were determined using PDQuest software, with identification on the basis of MALDITOFmass spectra. Results: Compared with normal colorectal mucosa, protein abnormal expression of 65 spotsvarying more than 1.5 times were found in 2-DE gels from colorectal cancer samples (P<0.05); forty-two proteinswere up-regulated and 23 were down-regulated; twelve protein spots were identified using mass spectrometry,of which 8 were up-regulated, includimng HSPB1and Annexin A4, while 4 were down-regulated, the resultsbeing consistent with Western blot findings. Conclusions: Two-dimensional electrophoresis reference maps forCRC tissues and adjacent normal mucosa (NMC) were established and 12 differentially expressed proteinswere identified. Up-regulated HSPB1 and Annexin A4 may play many important roles in the pathogenesis ofcolorectal cancer.
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