IRF4 mutations in CLL. (A). Schematic representation of the L116R mutation. (B) Chromatographs of L116R and L116P mutations. (C) Clinical characteristics of patients showing IRF4 mutations. (D) Significantly overexpressed genes in HEK 293 cells transfected with IRF4 L116R versus WT IRF4. (E-F) Mutant and WT IRF4 mRNA levels in CLL samples and transfected HEK 293 cells. (G) Expression of IRF4 L116R mutant increases apoptosis in K562 cells (representative experiment is shown). (H) Expression of IRF4 L116R mutant increases caspase-3/caspase-7 activity in K562 cells. Reaction was stopped at the indicated time points.