Abstract: Objective  To investigate the influence of phosphatase and tensin homologue deleted on chromosome ten(PTEN) in invasion of tongue squamous cell carcinoma  and to clarify the relationship between PTEN and epithelial-mesenchymal transition (EMT) in tongue squamous cell carcinoma. Methods  The SCC-4（non-transfection group）,pEGFP-PTEN-SCC-4（transfection group） and pEGFP-SCC-4（empty vector group）were cultivated at the same time. The cell invasion was observed by Transwell assay.The expressions of E-cad，snail and vimentin proteins  were examined by Western blotting.Results The number of the cells which passed the membrane were:82±5,80±4 and 42±5 in non-transfection group，empty vector group and transfection group 36 h after culture in Transwell assay;there was no significant difference between non-transfection group and empty vector group (P>0.05),but there was significant difference between non-transfection group and transfection group (P<0.001).Compared with non-transfection group,the E-cad expression was up-regulated(P<0.05),and the expressions of vimentin and snail were down-regulated(P<0.05) in transfection group;but there was no significant different between non-transfection group and empty vector group (P>0.05).Conclusion PTEN may  reduce the invasion of tongne squamous cell carinoma SCC-4 cells by inhibiting the EMT process of tumor cells.

Key words: phosphatase and tensin homologue gene d
eleted on chromosome ten, tongue sq
uamous cell carcinoma, epithelial-mesenchymal transition, invasion