ANGPT2 and neoplasm: The angiogenesis process is triggered and promoted by angiogenic factors, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), hypoxia-inducible factor 1-alpha (HIF1α), angiopoietin 1 (Ang-1), and angiopoietin 2 (Ang-2) that are mainly derived from tumor cells, glial cells, and stromal cells [3,4,5].