AKT2 and cancer: For instance, AKT1, AKT2, and AKT3, belonging to the five pathways of signaling by GPCR, GPCR downstream signaling, innate immune system, adaptive immune system, and developmental biology, are three isoforms of AKT in PI3K/AKT pathway, which is an important drug target in many cancers including GBM [30].