Levels of basic fibroblast growth factor (bFGF), vascular endothelial factor (VEGF), IL-8 and CCL2 are increased in the BM plasma from ALL patients, and these growth factors can enhance angiogenesis and increase the adhesion of ALL cells to BM stromal cells; in some cases, these growth factors may contribute to the development of ALL12, 13. This evidence concerns the gene CCL2 and acute lymphoblastic leukemia.