Open Access Research

Prognostication of prostate cancer based on TOP2A protein and gene assessment: TOP2A in prostate cancer

Marina França de Resende1, Samantha Vieira1, Ludmilla Thomé Domingos Chinen1, Francesco Chiappelli2, Francisco Paulo da Fonseca1, Gustavo Cardoso Guimarães3, Fernando Augusto Soares1, Ivan Neves1, Simone Pagotty1, Peter A Pellionisz2, Andre Barkhordarian2, Xenia Brant1 and Rafael Malagoli Rocha14*

Author Affiliations

1 Department of Pathology, A. C. Camargo Cancer Hospital, Sao Paulo, Brazil

2 UCLA School of Dentistry, Los Angeles, CA, USA

3 Department of Urology, A. C. Camargo Cancer Hospital, Sao Paulo, Brazil

4 Rua Professor Antônio Prudente 211, Liberdade São Paulo, SP, 01509-900, Brazil

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Journal of Translational Medicine 2013, 11:36  doi:10.1186/1479-5876-11-36

Published: 11 February 2013

Abstract

Background

TOP2A encodes for topoisomerase IIα, a nuclear enzyme that controls DNA topological structure and cell cycle progression. This enzyme is a marker of cell proliferation in normal and neoplastic tissues; however, little information is available about its expression in prostate cancer (PCa).

Methods

Immunohistochemistry (IHC) was automated using mouse monoclonal antibody against TOP2A (clone SWT3D1; DAKO, Carpenteria, CA, USA) at dilution 1:800 and Flex Plus detection system in autostainer 48Ultra (DAKO). FISH was performed using TOP2A (17q21)/ CEP17 probe kit (Kreateck Biotechnology, San Diego, CA, USA). Biochemical and pathological data from 193 patients with PCa were retrieved for the analysis, whose significance was considered when p < 0.05. Also, fractal analysis was performed in a subset of 20 randomly selected cases.

Results

TOP2A protein expression correlated with higher Gleason scores and higher levels of preoperative PSA (p = 0.018 and p = 0.011). Patients with higher levels of TOP2A presented shorter biochemical recurrence-free survival (BRFS) (p = 0.001). In multivariate analysis, we found that TOP2A remained an independent prognostic factor of BRFS, with a relative risk of 1.98 (p = 0.001; 95% CI, 1.338–2.93); thus, cases that expressed high levels of this enzyme had a shorter BRFS compared with TOP2A-negative or TOP2A-low cases. No alterations in TOP2A gene status nor correlation between FISH and IHC results were observed. Concerning fractal analysis, patients who expressed higher levels of TOP2A have angiolymphatic invasion and presented higher Gleason scores (p = 0.033 and p = 0.025, respectively). Also, patients with higher expression of TOP2A presented shorter BRFS (p = 0.001).

Conclusions

This is the first study to perform TOP2A protein and gene digital assessment and fractal analysis in association with BRFS in a large series of PCa. Also, we show that TOP2A gene copy number alterations are not observed in this type of tumor. So, higher protein expression of TOP2A is not related to gene amplification in PCa. Furthermore, TOP2A protein assessment has prognostic importance and, due to its relation with poor outcome, TOP2A IHC evaluation in the biopsy can represent an important tool for selecting the most suitable surgical and clinical approach for patients with PCa.

Keywords:
FISH; Immunohistochemistry; Prostate cancer; TOP2A