TOP2A and cancer: Some occurred at genes with established clinical significance in breast cancer, such as the amplification of cyclin D1 (CCND1) (Arnold and Papanikolaou 2005) on Chromosome 11 and topoisomerase (DNA) II alpha (TOP2A) (Engstrom et al. 2014) on Chromosome 17, while others occurred at genes for which experimental evidence exists for involvement in cancer, such as the homeobox protein SIX6 (Soulier et al. 2005) on Chromosome 14 and PREX1 (Sosa et al. 2010) on Chromosome 20.