Implications of Topoisomerase (TOP1 and TOP2α) Expression in Patients With Breast Cancer

Background/Aim: We evaluated the usefulness of topoisomerases (TOPs) expression as prognostic predictors in breast cancer. Patients and Methods: We retrospectively investigated sixty cases with primary breast cancer. We evaluated the tumor and non-tumor mRNA levels of TOP1 and TOP2 alpha using quantitative reverse-transcription polymerase chain reaction. TOP1/TOP2 alpha positivity was defined as the ratio of the mRNA expression of cancer/normal tissue of >1 for both TOP1 and TOP2 alpha. Results: TOP1 and TOP2 alpha were markedly overexpressed in breast cancer tissues compared to normal breast tissues. Of the 60 cases, 46 (76.7%) were positive for TOP1/TOP2 alpha. The relapse-free survival was relatively shorter for patients with positive TOP1/TOP2 alpha. There was no recurrent disease among the 14 patients who were negative for TOP1/TOP2 alpha, whereas four of the 46 TOP1/TOP2 alpha-positive patients had disease recurrence. Conclusion: Negative TOP1 or TOP2 alpha expression may be useful for predicting better prognoses in breast cancer patients.