Objective:The aim of the present study was to analyze the prognostic factors in patients with hepatoblastoma (HB) in our single center and to evaluate periostin (POSTN) expression in HB and its association with clinicopathological variables.In addition,the underlying mechanism of how POSTN promotes HB progression was discussed.Methods:POSTN expression was investigated in HB tumors by immunohistochemistry (IHC),immunofluorescence (IF) and West blot (WB).The association among POSTN expression,clinicopathological features and overall survival (OS) was also evaluated.The migration and adhesion ability of HB cells were measured using chemotaxis and cell-matrix adhesion assays,respectively.Epithelial-mesenchymal transition (EMT)-associated markers and activation of the ERK pathway were detected by WB.Results:HB patients had poor prognosis which displayed lymph node metastasis,vascular invasion,POSTN and vimentin expression.POSTN expression was also associated with lymph node metastasis.Furthermore,overexpressed POSTN promoted migration and the adhesive ability of HB cells in vitro.In addition,we demonstrated that POSTN activated the MAPK/ERK pathway,upregulated the expression of Snail and decreased the expression of OVOL2.Finally,POSTN promoted the expression of EMT-associated markers.Conclusions:POSTN might modulate EMT via the ERK signaling pathway,thereby promoting cellular migration and invasion.Our study also suggests that POSTN may serve as a therapeutic biomarker in HB patients.