The MAP kinase pathway is activated by ligand binding to a transmembrane receptor, which switches Ras on via GEF (Guanine nucleotide Exchange Factor) that counteracts GAP (GTPase Activating Protein) activity. Ras-GTP in turn activates the downstream signaling intermediates (kinases), which are activated by sequential phosphorylation. Which drug CANNOT be used to target cancer cells that have elevated receptor activation