Prognostic impact of topoisomerase IIα protein expression with regard to hormone status. Patients with tumors positive for topoisomerase IIα in more than 25% of tumor cells (solid lines) were compared with those having tumors expressing topoisomerase IIα in less than 25% of cells (dashed lines) with regard to the hormone status. The difference was significant in tumors positive for estrogen receptor or progesterone receptor (log rank 12.0; P = 0.0005).
Fritz et al. Breast Cancer Research 2005 7:R374-R384 doi:10.1186/bcr1012