PTEN and carcinoma: It has been reported that the expression of PTEN was decreased in RR cells of gastric[15] and nasopharyngeal[14] carcinoma, meanwhile, others find PTEN to be essential for attenuation of invasion and EMT.[11, 29] We found the expression of PTEN to be downregulated after FIR, and overexpression of PTEN restored the phenotype of KYSE/150/RR cells from the mesenchymal morphology to the epithelial morphology, accompanied with decreased migration and invasion.