CCNB1 and Ewing sarcoma: Moreover, while not specifically functionally implicated in Ewing Sarcoma, PDCD4 has been identified as an EWS/Fli1-repressed gene, while AURKB, CCNB1, CDCA7 and AURKA have been identified as EWS/Fli1-induced genes [32], thus also suggesting potential roles in Ewing Sarcoma cell proliferation and survival.