Topo II α

Topoisomerase II α (TopoIIα) is a core enzyme that regulates DNA topological structure and maintains cell proliferation. It can catalyze the producing of the DNA double-strand gap, making the broken double strands pass through the gap and then reconnect to prepare for DNA replication. TopoIIα is an essential protein in the cell cycle. It is maximally expressed in G2 and M phases but not in G0 and G1 phases. Therefore, TopoIIα can be used as a proliferative cell biomarker, widely applied to the research of lung cancer, gastric cancer, colorectal cancer, prostate cancer, breast cancer, cervical cancer and other tumors, and its high expression is closely related to the high invasiveness of cancer cells and the poor prognosis of patients. Some scholars believe that overproduced TopoIIα can cause the inactivation of P53 and RB1 in prostate cancer cells. And in breast cancer, TopoIIα abnormal expression is associated with HER2 gene amplification, which may be because their genes are in close proximity. On the other hand, TopoIIα is a target of anthracyclines, so its high expression indicates that tumors have higher chemotherapy sensitivity.