1. Department of Otorhinolaryngology, Head and Neck Surgery Medical University of Vienna Vienna Austria
2. Institute of Head and Neck Diseases Evangelical Hospital Vienna Vienna Austria
3. Department of Surgical Oncology Shaukat Khanum Memorial Cancer Hospital and Research Center Lahore Pakistan
4. Department of Clinical Pathology Medical University of Vienna Vienna Austria
5. Department of Otorhinolaryngology, Head and Neck Surgery Mistelbach Hospital Mistelbach Austria