We previously described an oncogenic mechanism of aberrant YAP1/Hippo signaling activation mechanistically based on the FUS-DDIT333 and SS18-SSX34 oncoproteins in MLS and SySa which is to some extent reminiscent of the situation in alveolar rhabdomyosarcoma in which the pathognomonic PAX3-FOXO1 protein promotes tumorigenesis by Hippo pathway suppression8. This evidence concerns the gene FOXO1 and alveolar rhabdomyosarcoma.