Table 1.

List of important angiogenesis stimulators and their specified roles.

Angiogenesis Stimulator	Role in the Angiogenesis Process	Reference
HIF-1α	Regulate angiogenesis and cell invasion	[10,11,28,42,58,59]
VEGF	Inducer of angiogenesis and lymph-angiogenesis, and activates the other angiogenic stimulators	[67,68,69,70,71,72]
PDGF	Stimulates angiogenesis, regulates cell growth and division	[73,74,75,76,77]
FGF	Regulates endothelial cell proliferation, migration, and differentiation	[78,79,80,81,82]
TGF- β	Induces apoptosis, plays a tumor-suppressor role at an early stage of tumor development, and acts as a tumor promoter in the later stage of tumor progression	[83,84,85,86,87]
ANG1, ANG2	Regulates angiogenesis and stimulates matured vessel formation	[88,89,90,91,92,93,94]
EPO	Promotes erythropoiesis and tumor cell survival	[32,95,96,97,98]

Abbreviations: ANG 1: Angiopoietin 1; ANG 2: Angiopoietin 2; EPO: erythropoietin; FGF: Fibroblast growth factor; HIF-1α: Hypoxia-inducible factor-1α; PDGF: Platelet-derived growth factor; TGF: Transforming growth factor; VEGF: Vascular endothelial growth factor.