PDGFRB and isolated hemihyperplasia: Apart from the PI3K/AKT/MTOR and RAS/RAF/ERK signaling pathways, other signaling pathways are also involved in VAs: VEGF-A/VEGFR2 signaling and PDGFB/PDGFRB Signaling Pathway in vascular tumors (IH) and HGF [hepatocyte growth factor])/c -Met signaling in glomuvenous malformations (GVMs) [4].