As CXCL12 regulates hematopoietic cell trafficking to positioning in the BM [20], it is not surprising that aberrant CXCR4 expression on cancer cells from several hematopoietic malignancies influences neoplasia progression by controlling cancer cell migration to BM as well as to lymph nodes, suggesting CXCR4 as a novel, reliable prognostic biomarker [21]. This evidence concerns the gene CXCR4 and cancer.