In the context of GB, the presence of glioma-initiating cells (GICs) has also been demonstrated, and miR-33a expression promotes their growth and self-renewal by directly interacting with the mRNAs encoding phosphodiesterase 8A (PDE8A) and UV radiation-resistance-associated gene (UVRAG) genes, which are known to negatively regulate the cAMP/PKA and NOTCH pathways, respectively [63]. Here, PDE8A is linked to central nervous system cancer.