TACR1 and glioblastoma: Knockdown of nine PTGs significantly decreased cell viability (Fig. 3d and Extended Data Fig. 4d), of which lower expression levels of DRD1, DRD2, HTR3A and TACR1 were also associated with better patient survival in The Cancer Genome Atlas (TCGA) glioblastoma cohort (Extended Data Fig. 4e).