The identification of patients with high-risk prostate cancer (PC) is a major challenge for clinicians, and the improvement of current prognostic parameters is an unmet clinical need. We and others have identified an association between the nuclear localization of NF-κB p65 and biochemical recurrence (BCR) in PC in small and/or single-centre cohorts of patients.

In this study, we accessed 2 different multi-centre tissue microarrays (TMAs) representing cohorts of patients (Test-TMA and Validation-TMA series) of the Canadian Prostate Cancer Biomarker Network (CPCBN) to validate the association between p65 nuclear frequency and PC outcomes. Immunohistochemical staining of p65 was performed on the Test-TMA and Validation-TMA series, which include PC tissues from patients treated by first-line radical prostatectomy (n = 250 and n = 1,262, respectively). Two independent observers evaluated the p65 nuclear frequency in digital images of cancer tissue and benign adjacent gland tissue. Kaplan-Meier curves coupled with a log-rank test and univariate and multivariate Cox regression models were used for statistical analyses of continuous values and dichotomized data (cutoff of 3%). Multivariate analysis of the Validation-TMA cohort showed that p65 nuclear frequency in cancer cells was an independent predictor of BCR using continuous (hazard ratio [HR] 1.02 [95% CI 1.00-1.03], p = 0.004) and dichotomized data (HR 1.33 [95% CI 1.09-1.62], p = 0.005). Using a cutoff of 3%, we found that this biomarker was also associated with the development of bone metastases (HR 1.82 [95% CI 1.05-3.16], p = 0.033) and PC-specific mortality (HR 2.63 [95% CI 1.30-5.31], p = 0.004), independent of clinical parameters. BCR-free survival, bone-metastasis-free survival, and PC-specific survival were shorter for patients with higher p65 nuclear frequency (p < 0.005). As the small cores on TMAs are a limitation of the study, a backward validation of whole PC tissue section will be necessary for the implementation of p65 nuclear frequency as a PC biomarker in the clinical workflow.

We report the first study using the pan-Canadian multi-centre cohorts of CPCBN and validate the association between increased frequency of nuclear p65 frequency and a risk of disease progression.

PLoS medicine. 2019 Jul 02*** epublish ***

Andrée-Anne Grosset, Véronique Ouellet, Christine Caron, Gabriela Fragoso, Véronique Barrès, Nathalie Delvoye, Mathieu Latour, Armen Aprikian, Alain Bergeron, Simone Chevalier, Ladan Fazli, Neil Fleshner, Martin Gleave, Pierre Karakiewicz, Louis Lacombe, Jean-Baptiste Lattouf, Theodorus van der Kwast, Dominique Trudel, Anne-Marie Mes-Masson, Fred Saad, Canadian Prostate Cancer Biomarker Network

Centre de recherche du Centre hospitalier de l’Université de Montréal, Centre hospitalier de l’Université de Montréal, Montreal, Quebec, Canada., Research Institute of the McGill University Health Centre, McGill University Health Centre, Montreal, Quebec, Canada., Axe Oncologie, Centre de recherche du Centre hospitalier universitaire de Québec-Université Laval, Centre hospitalier universitaire de Québec-Université Laval, Quebec, Quebec, Canada., Vancouver Prostate Centre, Vancouver, British Columbia, Canada., University Health Network, Toronto, Ontario, Canada.