PDGFRB and hereditary hemorrhagic telangiectasia: Pazopanib and nintedanib could have similar efficacy in HHT, as both are multi-tyrosine kinase inhibitors and inhibit a number of growth factors, such as vascular endothelial growth factor receptors (VEGFR-1, -2, and -3), platelet-derived growth factor receptors (PDGFR-ɑ and -β), stem cell factor receptor (c-Kit), and (FGFR-1 and -3).