Renu Jeyapala1, Andrea J Savio2, Ekaterina Olkhov-Mitsel2, Shivani Kamdar2, Fang Zhao2, Carmelle Cuizon2, Richard S C Liu2, Alex Zlotta3, Neil Fleshner3, Theodorus van der Kwast4, Bharati Bapat5. 1. Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada. 2. Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada. 3. Departments of Surgery and Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada. 4. Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Pathology and Laboratory Medicine, University Health Network, Toronto, Canada. 5. Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Departments of Surgery and Surgical Oncology, Division of Urology, University Health Network, Toronto, Canada; Department of Pathology and Laboratory Medicine, University Health Network, Toronto, Canada. Electronic address: bapat@lunenfeld.ca.
Abstract
BACKGROUND: Tumor intraductal carcinoma/cribriform architecture (IDC/C) is associated with an unfavorable prognosis and biochemical recurrence (BCR) in prostate cancer (PCa). Up to 70% of PCa patients are IDC/C-negative, but it is estimated that 20% of these cases still experience BCR. Thus, biomarkers for better detection of aggressive disease in IDC/C-negative patients are required. OBJECTIVE: To investigate tumor-specific methylation of the transcription factor GBX2 as a novel prognosticator and predictor of BCR in PCa patients stratified by histopathologic features including IDC/C. DESIGN, SETTING, AND PARTICIPANTS: Using genome-wide methylome profiling, we identified higher GBX2 methylation in grade group (GG) 4 tumors compared to GG1 (discovery cohort). The prognostic nature of GBX2 methylation was validated in silico using The Cancer Genome Atlas data (n=478) and a quantitative methylation assay for radical prostatectomy samples (n=254). Regulation of GBX2 methylation was investigated in prostate cells using methyl-CpG-binding domain sequencing and methylation analysis in functional knockouts of TET2, a key epigenetic player in prostate carcinogenesis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The association of GBX2 methylation with Gleason score (GS), pathologic stage (pT), IDC/C, and BCR was analyzed using Kruskal-Wallis and Mann-Whitney tests. Univariate and multivariate Cox regression analyses were used to predict BCR. RESULTS: GBX2 methylation was associated with GS (p<0.05), pT (p<0.01), and BCR (p<0.05). GBX2 methylation (p=0.004), GS (p<0.001), pT (p=0.012), and prostate-specific antigen (p=0.005) were independent predictors of BCR. Among IDC/C-negative patients, GBX2 methylation improved prediction of BCR (p=0.002). Loss of TET2 in prostate cells resulted in greater GBX2 methylation. CONCLUSIONS: We identified GBX2 methylation as a novel prognostic factor in PCa and an independent predictor of BCR. We demonstrated the additive value of GBX2 methylation in predicting BCR among IDC/C-negative patients and elucidated a novel TET2-mediated upstream epigenetic regulatory mechanism of GBX2. PATIENT SUMMARY: We identified GBX2 methylation as a promising prognostic biomarker that could improve the identification of prostate cancer patients at higher risk of biochemical recurrence.
BACKGROUND:Tumorintraductal carcinoma/cribriform architecture (IDC/C) is associated with an unfavorable prognosis and biochemical recurrence (BCR) in prostate cancer (PCa). Up to 70% of PCa patients are IDC/C-negative, but it is estimated that 20% of these cases still experience BCR. Thus, biomarkers for better detection of aggressive disease in IDC/C-negative patients are required. OBJECTIVE: To investigate tumor-specific methylation of the transcription factor GBX2 as a novel prognosticator and predictor of BCR in PCa patients stratified by histopathologic features including IDC/C. DESIGN, SETTING, AND PARTICIPANTS: Using genome-wide methylome profiling, we identified higher GBX2 methylation in grade group (GG) 4 tumors compared to GG1 (discovery cohort). The prognostic nature of GBX2 methylation was validated in silico using The Cancer Genome Atlas data (n=478) and a quantitative methylation assay for radical prostatectomy samples (n=254). Regulation of GBX2 methylation was investigated in prostate cells using methyl-CpG-binding domain sequencing and methylation analysis in functional knockouts of TET2, a key epigenetic player in prostate carcinogenesis. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The association of GBX2 methylation with Gleason score (GS), pathologic stage (pT), IDC/C, and BCR was analyzed using Kruskal-Wallis and Mann-Whitney tests. Univariate and multivariate Cox regression analyses were used to predict BCR. RESULTS:GBX2 methylation was associated with GS (p<0.05), pT (p<0.01), and BCR (p<0.05). GBX2 methylation (p=0.004), GS (p<0.001), pT (p=0.012), and prostate-specific antigen (p=0.005) were independent predictors of BCR. Among IDC/C-negative patients, GBX2 methylation improved prediction of BCR (p=0.002). Loss of TET2 in prostate cells resulted in greater GBX2 methylation. CONCLUSIONS: We identified GBX2 methylation as a novel prognostic factor in PCa and an independent predictor of BCR. We demonstrated the additive value of GBX2 methylation in predicting BCR among IDC/C-negative patients and elucidated a novel TET2-mediated upstream epigenetic regulatory mechanism of GBX2. PATIENT SUMMARY: We identified GBX2 methylation as a promising prognostic biomarker that could improve the identification of prostate cancerpatients at higher risk of biochemical recurrence.
Authors: Adam B Weiner; Farzana A Faisal; Elai Davicioni; R Jeffrey Karnes; Donald J Vander Griend; Tamara L Lotan; Edward M Schaeffer Journal: Eur Urol Oncol Date: 2020-06-12