CXCL12 and B-cell chronic lymphocytic leukemia: Compared to MDS-derived mesenchymal stromal cells (MDS-MSCs), MSCs from B-CLL patients produce aberrant SDF-1, B-cell activating factor (BAFF), and transforming growth factor β (TGF-β) resulting in exponentially promoted normal B-cell proliferation and IgG production [78].