Abstract: The sodium iodide symporter (NIS) is a transmembrane glycoprotein responsible for uptake of iodide into cells. It has raised the possibility of using radio-iodine for treatment of those tumors that cannot accumulate iodide. The NIS gene has been transferred into a variety of tumors and induced NIS functional expression successfully. However, the effect of therapy is disappointing. Hence, many investigators apply several different approaches to their studies and obtain more effective results.