The U.S. Food and Drug Administration has approved a test that helps in assessing the risk of tumor recurrence and long-term survival for patients with relatively high-risk breast cancer. The TOP2A FISH pharmDx is the first approved device to test for the TOP2A (topoisomerase 2 alpha) gene in cancer patients. The TOP2A gene plays a role in DNA replication. The TOP2A FISH pharmDx test uses fluorescently labeled DNA probes to detect or confirm gene or chromosome abnormalities, a technology known as fluorescent in situ hybridization (FISH).
Topoisomerase IIα is a key enzyme involved in DNA replication and is the molecular target for topoisomerase II inhibitor therapies. Clinical research shows that the TOP2A gene may prove to be an indicator of susceptibility or resistance to anthracycline therapies (1).