Therefore, to provide further insights into molecular mechanisms in topoII-related leukemias, we analyzed a cohort of 12 patients collected from across Europe who developed APL following the use of single agent mitoxantrone to treat a benign condition, multiple sclerosis (MS), and in whom there was no history of previous cancer.38 Chromosome 15 breakpoints again were found to cluster at position 1484 within PML intron 6. The gene discussed is PML; the disease is acute promyelocytic leukemia.