Awareness of the beneficial effect of blocking VEGF signaling in HHT patients dates back to 2006, when an HHT patient suffering from a malignant mesothelioma unexpectedly showed amelioration of HHT symptoms following antiangiogenic cancer treatment with an anti-VEGF-A monoclonal antibody (bevacizumab) (84). This evidence concerns the gene VEGFA and malignant mesothelioma.