TGFB1 and neoplasm: We have previously shown that MSCs expressing NIS under control of the tumor stroma-specific RANTES/CCL5 promoter 35, a HIF-1α-driven synthetic promoter activated by tumor hypoxia 37, or using a synthetic promoter responsive to transforming growth factor B1 (TGFB1) present in the tumor setting 43 can lead to a robust and efficient NIS expression within tumors.