Objective To investigate the expression of N6 methyladenine(m6A)demethylase human fat mass and obesity-associated(FTO)protein in nasopharyngeal carcinoma(NPC),and the effect of over-expression of FTO on the proliferation of nasopharyngeal carcinoma in vitro and in vivo.Methods Immunohistochemistry method was used to detect the expression of FTO protein in nasopharyngeal carcinoma tissues and para-cancerous tissues;The dominant expression cell line of FTO was screened,the over-expression FTO cell line was constructed.The cell pro-liferation was examined by soft-agar method.A mouse tumor model was developed for measurement of tumor growth.ResultsThe expression of FTO in nasopharyngeal carcinoma tissues was lower than that in adjacent tissues.Low ex-pression of FTO promoted proliferation of NPC cells,while over-expression of FTO reversed this effect.Conclusions FTO inhibits proliferation of nasopharyngeal carcinoma and this result may provide an experimental technology in searching therapeutic targets of chemotherapy for nasopharyngeal carcinoma.