Thus, the aim of the present study was to determine the mRNA expression pattern of seven representative CYPs (e.g., CYP1A1, CYP1A2, CYP1B1, CYP2E1, CYP2W1, CYP3A4, and CYP3A5) in paired tumor and normal tissue of childhood patients with RMS. This evidence concerns the gene CYP2W1 and neoplasm.