Transfection with siRNA to PRMT5 resulted in a significant enhancement of radiosensitivity in all three tumor cell lines U251, PSN1 and MDA-MB-231, with DEFs (Dose Enhancement Factor at a surviving fraction of 0.1) of 1.54, 1.41 and 1.53, respectively (Fig. 1C). This evidence concerns the gene PRMT5 and neoplasm.