EWSR1 and Ewing sarcoma: We recently reported that high expression of posterior Homeobox D gene cluster (HOXD) genes is a hallmark of Ewing sarcoma and that ectopic expression of EWS-FLI1 in neural crest-derived MSCs hijacks normal epigenetic regulation of HOXD10, HOXD11, and HOXD13 [17].