IRF4 was found to be differentially over-expressed, as compared to the healthy controls, in 30 patients (51.7% of total cohort): 26 ALL (18 B-common, 3 pre-B, 4 T-cell and 1 infant leukemia of unknown immunophenotype), 4 AML (1 with M1 and 3 with M5 maturation), and 3 of the 4 cell-lines: REH (pre-B ALL), CCRF-CEM (T-cell ALL) and THP-1 (AML) (Figure 1). This evidence concerns the gene IRF4 and acute myeloid leukemia.