A new study shows that breast cancer patients with an "amplification," or greater number of copies, of the TOP2A gene are 45% more likely than women who do not have this amplification to benefit from a longer course of anthracycline-based adjuvant chemotherapy.
The study - which is published online in the Journal of Clinical Oncology - suggests that TOP2A amplification could help oncologists further refine breast cancer therapy by identifying patients most likely to benefit from a more sustained duration of anthracyclines after surgery.
The TOP2A gene is associated with increased production of topoisomerase - a protein that accelerates cell division and is thought to encourage cancer growth and proliferation. Anthracyclines work by inhibiting the TOP2A gene. Previous research has shown that amplification of TOP2A occurs almost exclusively in patients who also have amplification of HER2/neu, another genetic biomarker currently used to guide breast cancer treatment.
"Increasingly, breast cancer treatment is being personalized based on the presence of molecular markers, such as HER2, and estrogen and progesterone receptors," said Jorma Isola, PhD, Professor of Cancer Biology at Tampere University, Finland and lead author of the study. "These findings indicate that the TOP2A gene could one day serve as an additional biomarker for breast cancer, helping to further refine adjuvant therapy for this disease."
Researchers performed an analysis of stored tissue samples obtained from 391 patients who had undergone treatment for breast cancer and were at highest risk for disease recurrence. Of the 391 tissue samples, 32.7% had amplification of HER2/neu, and 37% of those also had TOP2A amplification. All patients received initial adjuvant anthracycline-based chemotherapy and then were randomized to either continue on anthracycline-based chemotherapy or to undergo high-dose, non-anthracycline-based chemotherapy and stem-cell transplantation.