xCT overexpressing cells (xCTOE) are more resistant to the FDA and EMA approved drug sulfasalazine (Azulfidine/Salazopyrin/Sulazine®, SAS) and RNAi-mediated xCT knock down (xCTKD) in gliomas increases the susceptibility towards SAS in rodent gliomas. The gene discussed is SLC7A11; the disease is central nervous system cancer.