AKT1 and central nervous system cancer: Erlotinib has been reported to inhibit EGFR-dependent cellular proliferation in vitro by arresting the cell cycle in the phase G1, reducing the levels of cyclin D1, and increasing the expression of the protein p27kip1 (inhibitor of cyclin-dependent kinases), which induced the hypophosphorylation of pRB; additionally, it reduces glioma cell migration and invasion by inactivating the ERK, AKT, and RHO pathways [202].