JUN and acute lymphoblastic leukemia: It was also found that BM stromal cells are able to up-regulate IL-8 mRNA in T-ALL cells through the activity of CXCR4, and exogenous CXCL12 induced IL-8 mRNA synthesis in primary T-ALL cells, with consequent activation of nuclear factor –κB (NF- κB) and c-Jun (47).