1. Department of Head and Neck Surgery, The Permanente Medical Group, Santa Rosa, California, USA
2. Department of Radiation Oncology, The Permanente Medical Group, Rancho Cordova, California, USA
3. Division of Research, Kaiser Permanente Northern California, Oakland, California, USA
4. Department of Pathology, The Permanente Medical Group, Roseville, California, USA
5. Department of Health System Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California, USA