An involvement of PI3K in the acute effects of CB1 receptor stimulation has also emerged from a study on CB1-transfected CHO cells and CB1-expressing human U373 MG astrocytoma cells, where THC has been shown to enhance the activity of protein kinase B (PKB)/Akt [58]. The gene discussed is AKT1; the disease is astrocytoma (excluding glioblastoma).