TGFB1 and Ewing sarcoma: Given previous reports of increased TGFβ signaling in Ewing sarcoma cell populations with a pro-metastatic phenotype in vitro (34), we next compared rates of metastasis with ± TGFβ inhibition by examining lung tissue for the presence of metastases in the mice utilized in the experiments shown in both Figs. 5 and 6.