YAP1 and neoplasm: Immunohistochemical staining, tumor cells express vascular endothelial markers CD34, CD31, ERG and FLI-1, 25 to 30% of cases express CK (AE1/AE3 or CAM5.2) and EMA, Approximately 90% of EHEs have WWTR1-CAMTA1 gene fusion, and about10% of EHEs have YAP1-TFE3 gene fusion (28).