RUNX1 and leukemia: While the natural breakpoint observed in t(8;21) leukemia produces an AML1 exon 5 to ETO exon 2 fusion, Solari et al. described a rare novel AML1/ETO fusion transcript tightly associated with BCR/ABL, wherein the breakpoint lies one intron downstream, resulting in a fusion transcript including AML1 exon 6 [21].