Melatonin also shows indirect antiangiogenic effects, such as the inhibition of some tumor growth factors (IGF, EGF, and ET-1) which stimulate tumoral angiogenesis (Kajdaniuk et al., 2002) and the neutralization of reactive oxygen species which, in hypoxia, stabilize hypoxia-inducible factor HIF-α (Fandrey and Genius, 2000). Here, IGF1 is linked to neoplasm.