TACR1 and central nervous system cancer: Ding et al. developed neurokinin-1 receptor (NK1R) targeting vectors (SP-PEG4-K(C18)-(LLHH)3-R9) combining cell-penetrating, targeting, and endosomal escape domains to achieve specific transfection of glioma cells and successful blood-brain barrier (BBB) crossing in zebrafish models.