Furthermore, shared chromosome 17 breakpoints that were preferential sites of mitoxantrone-induced topoII cleavage in functional assays were identified within RARA intron 2 (Figure 1).38 The series of mitoxantrone-related t-APL cases analyzed has been further extended recently, with the chromosome 15 breakpoint found to fall within the “hotspot” region in 12 of 23 cases (52%).33,38,39. Here, RARA is linked to acute promyelocytic leukemia.