In a series of Ewing sarcoma samples analyzed by immunohistochemistry with an antibody that does not discriminate between YAP and TAZ and is ignorant to their phosphorylation status, 40% of primary tumors and ~70% of relapsed tumors and metastasis samples showed high YAP/TAZ expression, significantly correlating with a shortened time to relapse and adverse overall survival [215]. This evidence concerns the gene WWTR1 and Ewing sarcoma.