Topoisomerase II alpha (TOP2A) is a member of a highly conserved group of enzymes that solve the topological problems associated with double-stranded DNA replication, transcription, recombination, and chromatin remodeling by introducing single or double strand breaks into DNA. It is expressed in higher levels in replicating cells, and overexpression has been correlated with increased risk of progression in various cancers. TOP2A has been a target for the development of anti-polymerase inhibitors to treat cancer. It is expressed in the nucleus of highly proliferating cells. References: Ann Rev Bioc 2001 70:369; PlosOne 2015 10(11):e0142327; Mod Path 2009 22:579; Drug Discov ther 2012 6:230; Nat Rev Cancer 2009 9:338; Br Can Res Treat 1999 55:61.