PGF and obesity disorder: Adipocytes alter their adipokine profile in obesity, producing a plethora of pro-angiogenic factors including leptin, ceruloplasmin, angiopoietin-like proteins (e.g. ANGPTL2), hepatocyte growth factor (HGF) and proteins of the vascular endothelial growth factor (VEGF) family, including placental growth factor (PlGF), and hence promote an environment conducive to tumour growth [66].