Three different PDGFR tyrosine kinase inhibitors are currently under clinical investigation for the treatment of CRC, i.e., imatinib mesylate, sunitinib, and sorafenib, which all inhibit, in addition to PDGFR, other RTKs such as SCF, VEGF and KIT or the Raf cascade, respectively [30, 31]. The gene discussed is KITLG; the disease is colorectal carcinoma.