GRK5 and glioblastoma: GRK5 functions as oncogenes in glioblastoma (GBM) (Yang et al., 2018), prostate (Kim et al., 2012), pancreas (Tseng and Zhang, 2000), non-small-cell lung (Jiang et al., 2018), and breast (Sommer et al., 2019) cancers.