It is shown that CXCR4, a receptor for CXC chemokine receptor 12 (CXCL12), is a central player in migration and homing to tissue niches of leukemia cell that support cell survival, growth and drug resistance[23]; and has proved to be an adverse prognostic indicator of AML[24]. The gene discussed is CXCL12; the disease is acute myeloid leukemia.