CXCL12 and acute lymphoblastic leukemia: Since VD3-stimulated hMSC cells secreted 0.5 ng/ml of CXCL12 into the media (Fig. 5D), BCR-ABL ALL cells in suspension culture, or co-cultured with hMSCs, were treated with 0.5 ng/ml CXCL12 for 48 hr.