Secretion of TGF-β by activated platelets inhibits both the activation and function of NK cells.45 Transfer of major histocompatibility complex class I molecules from platelets to tumor cells might also allow them to evade lysis by NK cells (step two in Figure 1).46 Finally, platelets make extravasation and metastatic spread possible by promoting interactions between tumor cells and the vascular endothelium. The gene discussed is TGFB1; the disease is neoplasm.