IL21 and lymphoid leukemia: BIM up-regulation was already shown to be mediated by STAT1 in IL-21-treated lymphocytic leukaemia cells [69] and TNF-α+IFN-γ-exposed β-cells [26], while CHOP activity is required for BIM up-regulation and apoptosis induction in thapsigargin-treated thymocytes [45] and growth factor-deprived lymphoid precursors [70].