Exposure to environmental toxins and agents targeting topoII has been implicated in the development of infant leukemia with translocations involving MLL at 11q23.57–59 Interestingly, recent evidence lends further support for topoII in the etiology of chromosomal translocations, inducing DNA damage in the TMPRSS2 and ERG loci in response to androgen signalling, leading to formation of fusion genes involved in prostate cancer.60 The gene discussed is KMT2A; the disease is prostate cancer.