Apart from the factors above and downstream pathways shown in Fig. 3, Apelin/APLNR family,339 Slit/Robo family,340 adrenomedullin,341,342 COX-2,343,344 CXC chemokines,345,346 interleukins,347 interferons,348–350 nitric oxide synthase (NOS),351 pleiotrophin (PTN),352 steroid hormones,353 thrombospondin (TSP),354,355 and many other molecules also involve tumor angiogenesis to encourage tumor progression. The gene discussed is PTN; the disease is neoplasm.