PIK3CD and glioblastoma: Considering that the incidence and mortality of the brain and central nervous system tumors is 1.6% and 2.5% respectively in the worldwide (https://gco.iarc.fr/, Table 1), particularly the most common primary malignant tumor, glioblastoma multiforme (GBM), contributes to the poor prognosis partly for its tolerance of radiation therapy, hyper-activation of PI3K/AKT pathway in GBM caused by the mutations of PIK3CA or PIK3R1 (18.3%) and other PI3K family genes (6.8%) has urged researchers to seek novel targeted treatments to control the disease [17–19].