VEGFA and neoplasm: Tumour neovascularization is essential for the metastasis of some malignant tumours, and various proangiogenic factors are involved in tumour progression, including angiopoietin (Ang), platelet‐derived growth factor (PDGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), IL8 and matrix metalloproteinases (MMPs).41