title: Overexpression of CD9 correlates with tumor stage and lymph node metastasis in esophageal squamous cell carcinoma.
abstract: OBJECTIVE
  Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer deaths worldwide. CD9 has been reported to play a critical role in cell motility, growth and metastasis of multiple cancers. The present study investigated the clinicopathological features of CD9, and its biological characteristics in ESCC.
  
  
  METHODS
  Fifteen normal esophageal tissue specimens, fifty-three ESCC adjacent tissues and one hundred and four ESCC tissues were included in this study. Using immunohistochemistry (IHC), the expression levels of CD9 were evaluated among different samples. And its clinicopathological parameters and its prognostic factors were analyzed. Western blotting was used to measure CD9 expression and colony formation was performed to determine the effect of CD9 on cell growth in ESCC TE-1 cells.
  
  
  RESULTS
  Compared with normal esophageal tissues and tumor adjacent tissues, CD9 expression level is significantly higher in ESCC tissues. CD9 expression correlated with tumor stage (P=0.022) and lymph node metastasis (P=0.019) in ESCC patients. Furthermore, the small interfering RNA-mediated silencing of CD9 expression in TE-1 cells resulted in increased proliferation as evidenced by increased colony number and colony size.
  
  
  CONCLUSIONS
  CD9 expression is upregulated in ESCC tissues and its expression is correlated with tumor stage and lymph node metastasis in ESCC patients. CD9 suppresses the proliferation of TE-1 cells. CD9 may present a potential in tumor progression in ESCC.
authors.affiliation: Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University Suzhou 215004, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huan
authors.affiliation: Department of Gastroenterology, The Affiliated Jiangyin Hospital of Southeast University Jiangyin 214400, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Gao
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University Suzhou 215123, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University Suzhou 215123, China.
authors.forename: Wenjiong
authors.initials: W
authors.lastname: Sheng
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University Suzhou 215123, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University Suzhou 215123, China ; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University Suzhou 215123, China.
authors.forename: Shuyu
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University Suzhou 215123, China ; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University Suzhou 215123, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University Suzhou 215004, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Ji
authors.affiliation: Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University Suzhou 215004, China.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University Suzhou 215004, China ; Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University Suzhou 215123, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology*; D049109:Cell Proliferation; D004938:Esophageal Neoplasms / Q000378:metabolism / Q000473:pathology*; D000077277:Esophageal Squamous Cell Carcinoma; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D034741:RNA, Small Interfering / Q000235:genetics; D060245:Tetraspanin 29 / Q000032:analysis / Q000096:biosynthesis*; D014162:Transfection; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; C554869:CD9 protein, human; D034741:RNA, Small Interfering; D060245:Tetraspanin 29
keywords: CD9; Esophageal squamous cell carcinoma (ESCC); metastasis; proliferation