Abstract 428: Hypermethylation of GATA2 is validated as a marker of progression in non-muscle invasive bladder cancer
Authors: van Kessel Kim E.M. , van der Keur Kirstin A. , Dyrskjøt Lars , Algaba Ferran , Welvaart Naeromy , Beukers Willemien , Segersten Ulrika , Keck Bastian , Maurer Tobias , Simic Tatjana , Horstmann Marcus , Boormans Joost L. , Real Francisco X. , Malats Nuria , Malmström Per-Uno , Ørntoft Torben F. , Zwarthoff Ellen C. 
Published: July 2016

Abstract
Objective
Hypermethylation patterns of a set of four genes (GATA2, TBX2, TBX3, and ZIC4) were previously identified to predict progression of non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC). In this prospective study we aimed to validate these four genes as progression markers in NMIBC.
Materials and Methods
A total of 856 patients in follow-up for stage Ta urothelial carcinoma of the bladder were included in hospitals in Denmark, Germany, Serbia, Spain, Sweden and the Netherlands. Available pathology sections were reviewed by a single expert uropathologist. According to the WHO 2003 grading, 633 patients were diagnosed with a Ta low-grade tumor and 223 with a Ta high-grade tumor. Progression to muscle-invasive disease was seen in 18 (3%) of the low-grade tumors and in 12 (5%) of the high-grade tumors. Mean follow up was 22 months (range 0 to 76 months). DNA was isolated from fresh frozen tumor tissue and analyzed for mutations in FGFR3, TERT, RAS and PIK3CA. Methylation assays were done using a single-nucleotide probe extension assay for GATA2, TBX2, TBX3 and ZIC4. Methylation percentages were calculated and cut-off values were determined for dichotomization. All results were combined and the optimal model for predicting progression was selected by logistic regression analysis. Survival analysis was done using the Kaplan-Meier method.
Results
Multivariate logistic regression analysis using backward selection resulted in an optimal prediction model including GATA2, TBX2, age and gender for Ta low-grade tumors. The predictive capacity of the model represented by the AUC was 0.896. For Ta high-grade tumors, multivariate regression analysis resulted in a predictive model that included only GATA2 and smoking status with an AUC of 0.783. Mutation analysis did not add to these models. KM curves were plotted of the best performing methylation marker GATA2 and progression-free survival. Progression-free survival was significantly worse in patients having a GATA2-positive Ta high-grade tumor (P = 0.025).
Conclusion
Hypermethylation of the GATA2 gene can predict progression of NMIBC to MIBC in low- as well as high-grade Ta tumors. Further, survival is significantly worse in Ta high grade patients with a GATA2 positive primary tumor. Hypermethylation of GATA2 is therefore a validated progression marker for NMIBC.
Citation Format: Kim E.M. van Kessel, Kirstin A. van der Keur, Lars Dyrskjøt, Ferran Algaba, Naeromy Welvaart, Willemien Beukers, Ulrika Segersten, Bastian Keck, Tobias Maurer, Tatjana Simic, Marcus Horstmann, Joost L. Boormans, Francisco X. Real, Nuria Malats, Per-Uno Malmström, Torben F. Ørntoft, Ellen C. Zwarthoff. Hypermethylation of GATA2 is validated as a marker of progression in non-muscle invasive bladder cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 428.