Topoisomerase II a – a fundamental prognostic factor in breast carcinoma

Because of the introduction of modern diagnostic methods, numerous prognostic and predictive factors have been recognized and are today considered classic, yet they seem to be insufficient in assessment of prognosis, hence the need for further investigations. Among factors newly discovered by molecular techniques, there are class I and II topoisomerases, the role of which as prognosticators has not been fully determined. The objective of the present investigation was the assessment of topoisomerase II a (TOP2A) expression in patients with infiltrating breast carcinoma, as a prognostic factor in correlation with other recognized prognosticators and patient survival. The study was carried out in 151 patients treated by mastectomy and lymph node excision followed by adjuvant chemotherapy. The material was evaluated histopathologically according to the pTNM system, taking into consideration such parameters as grade of malignancy (G); the ER, PR as well as HER2 and TOP2A receptors status – all of them were assessed immunohistochemically. TOP2A was expressed with varying intensity in the majority of infiltrating ductal carcinomas studied, more frequently in large T3 and T4, grade G2 and G3 tumours, in patients with extensive metastases to regional N2 and N3 lymph nodes, a positive HER2 and negative ER and PR status. Five-year mortality rates were higher and 5-year symptom-free survival rates were lower in patients with TOP2A-postive tumours as compared to individuals with a negative TOP2A status. The study indicates that TOP2A expression is a negative predictive factor and may be recognized as a prognostic factor.