In light of our published studies that B-ALL cells produce high amounts of TNFα19,30 and that TNFα increases IL-6 expression in MSC4, we speculated that MSC and/or other cell types in the BMM conditioned by B-ALL cells are the likely source of IL-6 leading to hepatic generation of plasminogen. This evidence concerns the gene TNF and precursor B-cell acute lymphoblastic leukemia.