HACE1 and Ewing sarcoma: HACE1 was highly expressed in previously described osteoblast cell lines (OBB and OB1 (ref. 43)) compared to SJSA and SaOS-2 osteosarcoma cell lines (Fig. 1e), while HEK-293 cell line served as a positive control and Ewing sarcoma SK-NEP-1 cells as a negative control for HACE1 expression, as previously reported30,31.