IRF1 and acute promyelocytic leukemia: To validate this proposal, Green and colleagues [76] developed quantitative competitive RT-PCR assays to measure levels of full-length and exon-skipped IRF-1 transcripts (IRF-1∆2 and IRF-1∆2,3) in acute promyelocytic leukemia (APL), AML, and MDS patients, with a particular focus on those carrying an IRF-1 allele deletion.