title: Proteomic analysis of differentially expressed proteins involving in liver metastasis of human colorectal carcinoma.
abstract: BACKGROUND
  Early diagnosis of liver metastasis of colorectal carcinoma is very important for the appropriate treatment of such patients. However, there has been no effective approach available for clinical application. The present study aimed to investigate the differential expression of proteins in patients with liver metastasis of colorectal carcinomas using proteomic analysis and evaluate its potentiality in clinical diagnosis.
  
  
  METHODS
  Fluorescence two-dimensional differential in-gel electrophoresis (2-D DIGE) was used to analyze and compare the protein expression between normal mucosa, the primary focus, and liver metastases. Proteomic analysis was made to identify the differentially expressed proteins. Immunohistological staining was used to confirm the expression of differentially expressed proteins in colorectal carcinomas and areas of liver metastasis.
  
  
  RESULTS
  A 1.5-fold difference was found with 46 differentially expressed proteins. In 20 differentially expressed proteins, 3 were down-regulated and 17 up-regulated in liver metastases. Proteomic analysis showed that the S-adenosylmethionine transgelin variant was down-regulated in liver metastasis tissues. Zinc finger protein 64 homolog (Zfp64), guanine nucleotide exchange factor 4 (GEF4), human arginase, glutathione S-transferases (GSTs) A3, and tumor necrosis factor alpha (TNF-alpha)-induced protein 9 were up-regulated in liver metastasis tissues. Immunohistochemical staining confirmed that human arginase expression was higher in liver metastases than in the primary focus.
  
  
  CONCLUSIONS
  There was a significant difference in protein expression between the primary focus of colorectal carcinoma and liver metastases. The differentially regulated proteins were closely related to liver metastasis of colorectal carcinoma. Elevated human arginase may be an important molecular marker for liver metastasis from colorectal carcinoma.
authors.affiliation: Department of General Surgery, General Hospital of Beijing Military Command, Beijing 100700, China. lsybz@126.com
authors.forename: Shi-Yong
authors.initials: SY
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: An
authors.forename: Hui-Yun
authors.initials: HY
authors.lastname: Cai
authors.forename: Xue
authors.initials: X
authors.lastname: Bai
authors.forename: Ying-Nan
authors.initials: YN
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.forename: Fu-Yi
authors.initials: FY
authors.lastname: Zuo
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000473:pathology*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000737:chemistry / Q000556:secondary*; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D040901:Proteomics
chemical_list: D009363:Neoplasm Proteins