CTLs engaging tumour targets that do not present cognate antigen induce chemokinesis in distant CTLs, which could be mediated via the induced secretion of netrins, autotaxin, or semaphorins (Boneschansker et al., 2016; Katakai et al., 2014; Takegahara et al., 2005). This evidence concerns the gene ENPP2 and neoplasm.