The CXCR4 chemokine receptor, which has been closely linked with cancer cell growth, invasion, angiogenesis and metastasis, has been found to be overexpressed in various types of tumor, including breast cancer, ovarian cancer, glioma, pancreatic cancer, prostate cancer, acute myeloid leukemia as compared to normal cells, which show little or no CXCR4 expression (37–39). The gene discussed is CXCR4; the disease is breast carcinoma.