Ewing's sarcoma is a childhood/young adult cancer. Unfortunately, many Ewing's sarcoma cancer patients are first diagnosed when the cancer cells are already spreading throughout the body, and these patients have a very poor prognosis. Therefore, identifying novel means to improve the effectiveness of the standard treatment of this cancer, a cocktail of drugs that includes etoposide, would be of immediate benefit. This proposal will provide the basis for novel strategies in the treatment of human cancer.