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 expressio n with clinicopathological data and prognosis. Methods-Cryostat sectio ns from 63 primary invasive ductal breast carcinomas were stained immu nohistochemically for topoisomerase II-alpha. Nuclear immunoreactivity was quantified by counting at least 500 cells in different random fie lds and results were expressed as per cent of cells staining positivel y for topoisomerase II-alpha. Results-Topoisomerase II-alpha nuclear i mmunoreactivity (median 14% of nuclei; range 2-62%) was detected in al l rumours with highly variable intertumour and intratumour nuclear rea ctivity. Higher levels of topoisomerase II-alpha expression were stron gly related to higher tumour grade, larger tumour size, nodal status, and the presence of distant metastases at diagnosis. No correlation wa s found with menopausal status, steroid hormone receptor status, disea se free survival, or overall survival. Conclusions-Expression of topoi somerase II-alpha is related to the presence of poor prognostic factor s. Immunohistochemical assessment of topoisomerase II-alpha expression in breast cancer could be potentially useful for tailoring chemothera py with topoisomerase II inhibitors.