title: Presence of S100A9-positive inflammatory cells in cancer tissues correlates with an early stage cancer and a better prognosis in patients with gastric cancer.
abstract: BACKGROUND
  S100A9 was originally discovered as a factor secreted by inflammatory cells. Recently, S100A9 was found to be associated with several human malignancies. The purpose of this study is to investigate S100A9 expression in gastric cancer and explore its role in cancer progression.
  
  
  METHODS
  S100A9 expression in gastric tissue samples from 177 gastric cancer patients was assessed by immunohistochemistry. The expression of its dimerization partner S100A8 and the S100A8/A9 heterodimer were also assessed by the same method. The effect of exogenous S100A9 on motility of gastric cancer cells AGS and BGC-823 was then investigated.
  
  
  RESULTS
  S100A9 was specifically expressed by inflammatory cells such as macrophages and neutrophils in human gastric cancer and gastritis tissues. Statistical analysis showed that a high S100A9 cell count (> = 200) per 200x magnification microscopic field in cancer tissues was predictive of early stage gastric cancer. High S100A9-positive cell count was negatively correlated with lymph node metastasis (P = 0.009) and tumor invasion (P = 0.011). S100A9 was identified as an independent prognostic predictor of overall survival of patients with gastric cancer (P = 0.04). Patients with high S100A9 cell count were with favorable prognosis (P = 0.021). Further investigation found that S100A8 distribution in human gastric cancer tissues was similar to S100A9. However, the number of S100A8-positive cells did not positively correlate with patient survival. The inflammatory cells infiltrating cancer were S100A8/A9 negative, while those in gastritis were positive. Furthermore, exogenous S100A9 protein inhibited migration and invasion of gastric cancer cells.
  
  
  CONCLUSIONS
  Our results suggested S100A9-positive inflammatory cells in gastric cancer tissues are associated with early stage of gastric cancer and good prognosis.
authors: Department of Surgery, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital & Institute, Beijing, China.
authors: Biao
authors: B
authors: Fan
authors: Lian-Hai
authors: LH
authors: Zhang
authors: Yong-Ning
authors: YN
authors: Jia
authors: Xi-Yao
authors: XY
authors: Zhong
authors: Yi-Qiang
authors: YQ
authors: Liu
authors: Xiao-Jing
authors: XJ
authors: Cheng
authors: Xiao-Hong
authors: XH
authors: Wang
authors: Xiao-Fang
authors: XF
authors: Xing
authors: Ying
authors: Y
authors: Hu
authors: Ying-Ai
authors: YA
authors: Li
authors: Hong
authors: H
authors: Du
authors: Wei
authors: W
authors: Zhao
authors: Zhao-Jian
authors: ZJ
authors: Niu
authors: Ai-Ping
authors: AP
authors: Lu
authors: Ji-You
authors: JY
authors: Li
authors: Jia-Fu
authors: JF
authors: Ji
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D040501:Calgranulin A / Q000276:immunology / Q000378:metabolism; D040502:Calgranulin B / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D011379:Prognosis; D055503:Protein Multimerization; D013274:Stomach Neoplasms / Q000235:genetics / Q000276:immunology* / Q000401:mortality / Q000473:pathology*
chemical_list: D040501:Calgranulin A; D040502:Calgranulin B