The chemokine receptor CXCR4 involved in the trafficking of hematopoietic stem cells and cancer cells to bone is also expressed on MDSCs, and the CXCR4 antagonist AMD3465 decreased the intra-tumoral infiltration of MDSCs, increasing the survival of mice that received an intratibial inoculation of 4T1 breast cancer cells [291,292]. The gene discussed is CXCR4; the disease is breast cancer.