Immunohistochemical study of topoisomerase II-alpha expression in primary ductal carcinoma of the breast.
AIMS--To study the patterns of expression of topoisomerase II-alpha in primary invasive ductal breast carcinomas; to correlate this expression with clinicopathological data and prognosis. METHODS--Cryostat sections from 63 primary invasive ductal breast carcinomas were stained immunohistochemically for topoisomerase II-alpha. Nuclear immunoreactivity was quantified by counting at least 500 cells in different random fields and results were expressed as per cent of cells staining positively for topoisomerase II-alpha. RESULTS--Topoisomerase II-alpha nuclear immunoreactivity (median 14% of nuclei; range 2-62%) was detected in all tumours with highly variable intertumour and intratumour nuclear reactivity. Higher levels of topoisomerase II-alpha expression were strongly related to higher tumour grade, larger tumour size, nodal status, and the presence of distant metastases at diagnosis. No correlation was found with menopausal status, steroid hormone receptor status, disease free survival, or overall survival. CONCLUSIONS--Expression of topoisomerase II-alpha is related to the presence of poor prognostic factors. Immunohistochemical assessment of topoisomerase II-alpha expression in breast cancer could be potentially useful for tailoring chemotherapy with topoisomerase II inhibitors.