Prognostication of OCT4 isoform expression in prostate cancer.

Cancer stem cells (CSCs) refer to a subset of tumor cells that self-renew and affect tumor heterogeneity. This model has attracted considerable interest in recent years due to its implications in the prognosis and clinical management of cancer because CSCs mediate the occurrence, growth, and recurrence of tumors. OCT4 is central to embryonic stem cell self-renewal and differentiation into specific lineages and encodes two chief isoforms that are generated by alternative splicing--OCT4A and OCT4B. Their function in prostate cancer (PCa) is unknown. The prognostic function of OCT4 isoforms in PCa samples was examined by immunohistochemistry (IHC) and sensitivity and specificity of the antibodies used were evaluated by molecular biology techniques. Biochemical and pathological data and specimens from 193 patients with PCa were evaluated retrospectively. IHC, western blot, immunofluorescence, and automated image analysis were also performed. IHC was performed on a tissue microarray, and western blot and immunofluorescence were performed using the PCa cell line DU-145. IHC expression of OCT4 isoforms correlated with biochemical and pathological parameters, particularly biochemical recurrence-free survival (BCRFS). Patients with higher levels of OCT4B had lower Gleason scores and decreased likelihood of experiencing biochemical recurrence (BR). OCT4A(+) OCT4B(-) patients had the shortest BCRFS, and positivity for OCT4B expression was an independent prognostic factor for BCRFS in the multivariate analysis. We conclude that the expression of OCT4B is a strong marker of good prognosis, and its presence is associated with a decreased likelihood of BR. Thus, OCT4B might represent a powerful clinical prognostic biomarker for PCa patients.

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

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.