PTK inhibitors sunitinib, BGJ398, crizotinib, and imatinib did not inhibit any of the cell lines significantly, while gefitinib only inhibited one cell line, LS-513, with a modest IC50, suggesting that receptor PTKs in the PDGFR, EGFR, FGFR, MET, and soluble PTKs in the Abl families do not play major roles in driving the proliferation of CRC cells. The gene discussed is PDGFRB; the disease is colorectal carcinoma.