“…A diverse series of studies have demonstrated the efficacy of NIS-mediated radioiodide accumulation in a variety of non-thyroidal tumors using different gene delivery vehicles for NIS transgene expression (Niu et al 2004, Dwyer et al 2006, Klutz et al 2009, 2011a,b,c, Peerlinck et al 2009, Ahn et al 2010, Huang et al 2011, Knoop et al 2011, Grunwald et al 2013a,b,c, Mansfield et al 2016. The use of genetically engineered MSCs to deliver NIS into various types of tumors has been demonstrated in many studies (Dwyer et al 2011, Knoop et al 2011. Although these results have shown comparably high levels of NIS transgene expression in the tumor microenvironment followed by a therapeutic effect of 131 I, with a delay in tumor growth and prolonged survival of treated animals, the use of specific gene promoters for NIS expression that are activated by tumor micromileu-derived signals has been shown to enhance the selectivity and effectiveness and limit the potential offtarget effects following MSC recruitment to tissues as part of normal tissue homeostasis (Von Luttichau et al 2005, Klutz et al 2009, 2011a,b,c, Knoop et al 2011, Grunwald et al 2013a,b,c, Muller et al 2016.…”