Topoisomerase II alpha expression correlates with diminished disease-free survival in invasive breast cancer.

Abstract

Topoisomerase II alpha (Topo II alpha) plays a role in DNA replication and is the molecular target for anthracyline-based chemotherapy. The purpose of this study was to evaluate the relationship between Topo II alpha expression and survival in patients with invasive breast cancer. Formalin-fixed, paraffin-embedded tumor specimens from 24 women with invasive breast cancer were stained for Topo II alpha expression. All women underwent mastectomy. Radiotherapy was given at the University of Utah Department of Radiation Oncology. Of the patients, 23 (96%) received chemotherapy. The level of Topo II alpha expression within tumor cells was compared with clinical factors and overall survival. The median percentage of tumor cells expressing Topo II alpha was 70%. Increased Topo II alpha tumor expression significantly correlated with diminished disease-free survival. Five-year disease-free survival was 100% for patients with <70% of breast cancer cells expressing Topo II alpha compared with 42% for patients with > or =70% Topo II alpha expression (p = 0.008). The level of Topo II alpha expression within tumor cells correlated with T stage (p = 0.008) but not with other pathologic factors. Increased Topo II alpha expression significantly correlated with diminished disease-free survival in patients with invasive breast cancer. These findings may indicate a role for Topo II alpha expression as a prognostic factor in breast cancer.