These tumors are characterized by the fusion of a FET RNA-binding protein family gene, which includes Ewing sarcoma RNA binding protein 1 (EWSR1) and fused in sarcoma (FUS), to a cAMP response element-binding protein (CREB) family gene, which includes activating transcriptase factor-1 (ATF1), cAMP responsive element binding protein 1 (CREB1), cAMP response element modulator (CREM), and cAMP responsive element binding protein 3 like 3 (CREB3L3). Here, CREM is linked to sarcoma.