MAPK3 and glioblastoma: Increased phosphatidil-inositol-3-kinase/Akt/Protein kinase B (PI3K/Akt/PKB) and extracellular signal-regulated kinase (Erk1/2) pathway activation were found in invasive GBM cells [34–36], and a cross-talk between PI3K/Akt/PKB and Raf-1/MEK/Erk signaling pathways has been reported in GBM cells [37].