PDEδ (phosphodiesterase 6 delta) is a protein that binds to KRAS protein and regulates its orientation to membrane compartments.337,338 PDEδ has a large hydrophobic pocket that can bind farnesyl proteins, especially the lipid portion of KRAS protein, thereby preventing the farnesyl modification of KRAS protein from binding to cell membrane and inhibiting tumor cell proliferation and growth.339,340. The gene discussed is KRAS; the disease is neoplasm.