IRF9 and acute promyelocytic leukemia: Although the transcription factors IRF1 (UniProt: P10914) and IRF9 (UniProt: Q00978) have been implicated in the regulation of EVL in the context of long-term retinoic acid treatment of human promyelocytic leukaemia cells [43], it is not known whether the EVL promoter can be directly regulated by IFN and whether IFN signalling alone is sufficient for its induction [42].