IGF1 and neoplasm: Factors are involved in stimulating tumor angiogenesis indirectly by inducing VEGF, TGF-α and β, TNF-α, keratinocyte growth factor, insulin-like growth factor I (IGF-I), FGF, PDGF, and cytokines [interleukin (IL)-1α and IL-6 and EGF on tumor cells].