CXCR4 and acute lymphoblastic leukemia: Functionally, the suppressive effects of miR-139 on the proliferation of T-ALL cells were reversed by CXCR4 transfection, while the miR-139 overexpression substantially lowered the malignancy of T-ALL cells, and people with very high expression of miR-139 and reduced CXCR4 expression showed greater five-year survival than people with reduced miR-139 expression [22].