IRF4 and B-cell chronic lymphocytic leukemia: However, the associations implied by these two lines of studies appear to be incongruent: while the genome-wide association study results imply that the allele conferring the reduced expression of IRF4 is a risk allele (39), the mutational studies imply that the gain-of-function mutation (L116R) (52) and copy number gain (51) are drivers of CLL.