CXCL12 and precursor B-cell acute lymphoblastic leukemia: Although there is increasing evidence of the Nestin+CXCL12+ as one essential BM niche (11), dysregulation of CXCL12 and SCF related to pro-inflammatory microenvironment is a feature of ALL (22, 28, 39, 40); the CXCL10/CXCL11/CXCR3 axis has been implicated in chemotherapy resistance and CNS infiltration in B-ALL (47).