AIM:To investigate a potential role of S100A4 in esophagus squamous cell carcinoma metastasis (ESCCs).METHODS:Expression of S100A4 and E-cadherin were analyzed in frozen sections from ESCCs (metastasis,n =28; non-metastasis,n =20) by reverse transcription-polymerase chain reaction,quantitative polymerase chain reaction and immunohistochemistry.To explore the influence of S100A4 on esophageal cancer invasion and metastasis,S100A4 was overexpressed or silenced by S100A4 siRNA in TE-13 or Eca-109 cells in vitro and in vivo.RESULTS:We found the mRNA and protein levels of S100A4 expression in ESCCs was significantly upregulated,and more importantly,that expression of S100A4 and E cadherin are strongly negatively correlated in patients who had metastasis.It was indicated that overexpression of S100A4 in TE-13 and Eca-109 cells downregulates the expression of E-cadherin,leading to increased cell migration in vitro,whereas knockdown of S100A4 inhibited cell migration and upregulation of E-cadherin expression.Moreover,the loss of cell metastatic potential was rescued by overexpression of E-cadherin completely.In addition,nude mice inoculated with S100A4 siRNA-transfected cells exhibited a significantly decreased invasion ability in vivo.CONCLUSION:S100A4 may be involved in ESCC progression by regulate E-cadherin expression,vectorbased RNA interference targeting S100A4 is a potential therapeutic method for human ESCC.