Given that both the MAPK/ERK and PI3K/AKT/mTOR signaling cascades serve as major modulators of the oncogenic phenotype in both EWS and EWS-FLI1 expressing cancer cell lines (Silvany et al., 2000; Zenali et al., 2009), we chose U-0126, rapamycin, and LY294002 pharmacological agents (targeted inhibitors of ERK1/2, mTOR, and PI3K, respectively) for investigation in subsequent chemo-sensitivity studies. This evidence concerns the gene MAPK3 and cancer.