CX3CR1 and precursor B-cell acute lymphoblastic leukemia: Non-classical monocytes (CD14+CD16++) that exhibit high expression levels of CX3C motif chemokine receptor 1 (CX3CR1) are significantly elevated in the peripheral blood of B-ALL patients, and their abnormal recruitment is directly associated with BM stromal remodeling, which is mediated by the upregulation of CX3C chemokine ligand 1 (CX3CL1) in the BM [6].