Immunohistochemically, an increased expression of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9), angiopoietin-2 (ANG-2) and basic fibroblast growth factor (bFGF) was demonstrated in hypertrophic PWS [19]. This evidence concerns the gene FGF2 and Prader-Willi syndrome.