HEX effects on NIS promoter. HeLa cells were transfected with 1 and 2 μg of the HEX or PAX8 expression vector together with plasmids containing the NIS and the CMV promoters linked to the LUC and the βGAL reporter genes, respectively. The CMV-βGAL plasmid was used to normalize for efficiency of transfection. Each dot represents the mean value ± standard deviation of four independent transfections. Results are expressed as percentage of the values obtained in cells not transfected with HEX or PAX8 expression vectors.