Protein tyrosine kinase inhibitors as antiangiogenic agents

An essential element in cancer therapy is to inhibit the blood supply to the tumor. In this chapter, we discuss the few tyrosine phosphorylation inhibitors (tyrphostins/PTK inhibitors) that have been developed to achieve that goal. The inhibitors that block VEGFR2, PDGFR and EGFR and not solely VEGFR2 seem to do a better job towards this end. It is, however, not entirely clear that the anti-tumor effects observed with the agents described are entirely due to their antiangiogenic effects. This is because of the many other targets within the kinome they hit, which may be part of the oncogenic network, driving the cancers for which they were approved. None of the agents is life saving.