A 200-gene signature (11% FDR) characterized by overexpression of muscle-specific genes like ACTN3, CALD1, MBNL1, MLC1, MYH11, MYL4, SLMAP, TPM2 and TAGLN3 was identified in the leiomyosarcomas. The gene discussed is ACTN3; the disease is leiomyosarcoma.