The activation of PI3K/AKT pathway is important for proliferation of leukemia cells [9]; our data showed that MSC secreted-TRAIL suppressed PI3K/AKT pathway in B-ALL cells by downregulating the protein levels of leukemia proliferation-associated proteins PI3K, AKT, and the phosphorylation levels of MEK and ERK. The gene discussed is AKT1; the disease is leukemia.