title: In silico analysis and verification of S100 gene expression in gastric cancer.
abstract: BACKGROUND
  The S100 protein family comprises 22 members whose protein sequences encompass at least one EF-hand Ca2+ binding motif. They were involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. However, the expression status of S100 family members in gastric cancer was not known yet.
  
  
  METHODS
  Combined with analysis of series analysis of gene expression, virtual Northern blot and microarray data, the expression levels of S100 family members in normal and malignant stomach tissues were systematically investigated. The expression of S100A3 was further evaluated by quantitative RT-PCR.
  
  
  RESULTS
  At least 5 S100 genes were found to be upregulated in gastric cancer by in silico analysis. Among them, four genes, including S100A2, S100A4, S100A7 and S100A10, were reported to overexpressed in gastric cancer previously. The expression of S100A3 in eighty patients of gastric cancer was further examined. The results showed that the mean expression levels of S100A3 in gastric cancer tissues were 2.5 times as high as in adjacent non-tumorous tissues. S100A3 expression was correlated with tumor differentiation and TNM (Tumor-Node-Metastasis) stage of gastric cancer, which was relatively highly expressed in poorly differentiated and advanced gastric cancer tissues (P < 0.05).
  
  
  CONCLUSIONS
  To our knowledge this is the first report of systematic evaluation of S100 gene expressions in gastric cancers by multiple in silico analysis. The results indicated that overexpression of S100 gene family members were characteristics of gastric cancers and S100A3 might play important roles in differentiation and progression of gastric cancer.
authors.affiliation: Department of Gastrointestinal Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, 710032, PR China. liuji12@fmmu.edu.cn
authors.forename: Ji
authors.initials: J
authors.lastname: Liu
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Guang-Long
authors.initials: GL
authors.lastname: Dong
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Zhang
authors.forename: Dong-Li
authors.initials: DL
authors.lastname: Chen
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Du
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Zheng
authors.forename: Ji-Peng
authors.initials: JP
authors.lastname: Li
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D015152:Blotting, Northern; D020832:EF Hand Motifs; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D018709:Statistics, Nonparametric; D013274:Stomach Neoplasms / Q000235:genetics*
chemical_list: D009418:S100 Proteins; C082356:S100A3 protein, human
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