Topoisomerases are enzymes that catalyze changes in DNA and RNA topology to ensure DNA and RNA metabolisms (see the figure above). They are also molecular targets of anti-cancer therapies collectively known as topoisomerase inhibitors (topotecan, irinotecan, etoposide, doxorubicin, etc.). The Sun Lab at the University of Maryland School of Medicine, School of Pharmacy, and the Greenebaum Comprehensive Cancer Center studies topoisomerases, poly(ADP-ribose) polymerases, DNA repair, and their inhibitors for cancer treatment.