TGFB1 and neoplasm: Intriguingly, like its effect on tumor cell proliferation, TGF-β also has a paradoxical effect on angiogenesis; low levels of TGF-β promote angiogenesis by increasing the proliferation of endothelial cells and VEGFA expression, while high TGF-β levels hinders angiogenesis (Madri, Pratt, & Tucker, 1988; Pertovaara et al., 1994).