Department of Pathology, A. C. Camargo Cancer Hospital, Sao Paulo, Brazil.
J Transl Med. 2013 Feb 11;11:36. doi: 10.1186/1479-5876-11-36.
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).
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.
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).
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.
TOP2A 编码拓扑异构酶 IIα，这是一种控制 DNA 拓扑结构和细胞周期进程的核酶。该酶是正常和肿瘤组织中细胞增殖的标志物；然而，关于其在前列腺癌（PCa）中的表达知之甚少。
使用针对 TOP2A（克隆 SWT3D1；DAKO，加利福尼亚州卡彭特里亚）的小鼠单克隆抗体，通过自动免疫组织化学（IHC）在 Autostainer 48Ultra（DAKO）自动染色仪上进行稀释度为 1:800 的检测。使用 TOP2A（17q21）/CEP17 探针试剂盒（Kreateck Biotechnology，加利福尼亚州圣地亚哥）进行 FISH。对 193 例 PCa 患者的生化和病理数据进行了分析，当 p<0.05 时认为有统计学意义。此外，在 20 例随机选择的病例中进行了分形分析。
TOP2A 蛋白表达与较高的 Gleason 评分和术前 PSA 水平相关（p=0.018 和 p=0.011）。TOP2A 水平较高的患者生化无复发生存率（BRFS）较短（p=0.001）。在多变量分析中，我们发现 TOP2A 仍然是 BRFS 的独立预后因素，相对风险为 1.98（p=0.001；95%CI，1.338-2.93）；因此，与 TOP2A 阴性或 TOP2A 低的病例相比，表达高水平该酶的病例 BRFS 更短。未观察到 TOP2A 基因状态的改变，也未观察到 FISH 和 IHC 结果之间的相关性。关于分形分析，表达较高水平 TOP2A 的患者有血管淋巴管侵犯且具有较高的 Gleason 评分（p=0.033 和 p=0.025）。此外，TOP2A 高表达的患者 BRFS 较短（p=0.001）。
这是第一项在大型 PCa 系列中进行 TOP2A 蛋白和基因数字评估和分形分析与 BRFS 相关的研究。此外，我们表明在这种肿瘤中未观察到 TOP2A 基因拷贝数的改变。因此，TOP2A 蛋白的高表达与 PCa 中的基因扩增无关。此外，TOP2A 蛋白评估具有预后意义，由于其与不良预后相关，因此在活检中进行 TOP2A IHC 评估可以成为为 PCa 患者选择最合适的手术和临床方法的重要工具。
