1. Department of Neurosurgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
2. Seidman Cancer Center and Case Comprehensive Cancer Center, Cleveland, Ohio, USA
3. Department of Population and Quantitative Health Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
4. Central Brain Tumor Registry of the United States, Hinsdale, Illinois, USA
5. Department of Neurology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA