MYC and leiomyosarcoma: Indeed, c-Myc is upregulated in a number of sarcomas including leiomyosarcoma, osteosarcoma, chondrosarcoma, synovial sarcoma, ARMS and EwS.32–39 Myc is a basic helix–loop–helix zipper transcription factor that regulates its target genes by binding to a conserved E-box DNA sequence CACGTG.40 It mainly exerts its effect on the cell cycle by transcriptionally activating cyclins and CDKs or by repressing p15INK4b, p21CIP1, and p27KIP1.