MKI67 and plexiform neurofibroma: Furthermore, several signaling pathways involved in angiogenesis (cyclooxygenase 2, vascular endothelial growth factor A), cellular regulation (MKI67 etc.), epidermal growth factor (EGF receptor, pAKT, etc.)and Sonic hedgehog–Gli pathways are modified in plexiform neurofibromas associated with transformation [25].