P2RX4 and cancer: Moreover, given the involvement ofP2X4R in various CNS disorders and cancer, Positron Emission Tomography(PET) tracers could facilitate further investigation of this target.For these reasons, the development of potent and selective P2X4R antagonistsis currently a highly active area of research, as evidenced by thegrowing number of publications, including the FeaturedArticle by Erlitz et al., featured in this issue.1