To study the expression oflong noncoding RNA GAS5 (lncRNA-GAS5)in endometrial carcinoma and its role in regulation ofcellinvasion.M ethods Endometrialcarcinomas and the matched tumor adjacenttissueswere collected from 50 caseswho received surgicaltreatmentin ourhospitalbetween January 2013 and December2015.Theexpression oflncRNA-GAS5 wasdetected byqRT-PCR.LncRNA-GAS5 over-expression plasmid wastransfected into HEC-1A cells.Transwellinvasion assay modelwasused to measure cellinvasion.The expressions of miR -21 and PTEN were detected by qRT-PCR and W estern blot. Results The expression of lncRNA-GAS5 in the endometrialcarcinoma tissues was significantly lowerthan thatin the adjacenttissues( t=4.013, p< 0.05).Low expression oflncRNA-GAS5 wasassociated with lymphaticmetastasis ( t= 2.389, p= 0.017) and advanced FIGO stage (stage III and IV; t= 2.131, p= 0.021).Over-expression of lncRNA -GAS5 could significantly suppress the invasive ability of HEC-1A cells( t= 7.654,p = 0.008).Moreover,over-expression of lncRNA -GAS5 promoted miR -21 and PTEN expressions(p < 0.05).Conclusions lncRNA -GAS5 expression islowerd in endometrialcarcinoma tissuesand associated with cellinvasion.LncRNA-GAS5 may suppressmetastasis of endometrial carcinoma by inhibiting miR-21/PTEN axis.