CD44 and leukemia: A subset of leukemia cells, known as adhesive cells, express various adhesion molecules (including very late antigen-4 [VLA-4], intercellular adhesion molecule-1 [ICAM-1], cluster of differentiation 18 [CD18], lymphocyte function-associated antigen-1 [LFA-1], cluster of differentiation 58 [CD58], cluster of differentiation 44 [CD44], and vascular cell adhesion molecule [VCAM]), facilitating adhesion to vascular endothelial cells, leukocyte stasis in the vasculature, and promoting tumor growth and angiogenesis [11, 24].