For example, receptors that are highly expressed on the surface of glioma cells can allow for targeted delivery of agents into tumor BBB-disrupted regions, including interleukin-4 receptor (IL-4R) [44], interleukin-13 receptor (IL-13R) [45,46,47] and neurokinin-1 (NK-1) [48]. Here, IL4R is linked to central nervous system cancer.