We experimentally validated protein kinase Cδ (PKCδ) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) as the MKs that sustain cell growth and tumor cell identity of the glycolytic/plurimetabolic (GPM) and proliferative/progenitor (PPR) functional GBM subtypes, respectively. This evidence concerns the gene PRKCD and glioblastoma.