PRL and neoplasm: PRL promotes angiogenesis and is proteolytically cleaved into vasoinhibins, a family of peptides (including 16 kDa PRL) with potent antiangiogenic and blood vessel regression effects [33, 34]; 16 kDa PRL impairs functional tumor neovascularization by inhibiting vessel maturation and for the first time demonstrated that an endogenous antiangiogenic agent disturbs notch signaling [35].