AMD3100 (plerixafor), the most commonly used drug to inhibit the receptor CXCR4, is currently in clinical trials for glioma, leukemia, Ewing sarcoma, neuroblastoma and brain tumors and is already FDA-approved for Non-Hodgkin's lymphomas and multiple myeloma. The gene discussed is CXCR4; the disease is Ewing sarcoma.