IRF4 and acute myeloid leukemia: To test whether enforced FOXO1 expression is sufficient to induce EBF1, IRF4, or PAX5 expression in non-B-lineage blood cancer cells, we next transduced lentivirus encoding FOXO1 into the AML cell lines HEL and THP1, which express negligible levels of EBF1, FOXO1, IRF4, and PAX5 (Supplemental Figure 4A).