1. Department of Oral-, Maxillo- and Plastic Facial Surgery, Medical Faculty; University Hospital of the Heinrich-Heine-University Düsseldorf; Germany
2. Department of Otorhinolaryngology; Protestant Hospital Bethesda; Duisburg Germany
3. Department of General, Visceral and Pediatric Surgery, Medical Faculty; University Hospital of the Heinrich-Heine-University Düsseldorf; Germany
4. Department of Pathology, Medical Faculty; University Hospital of the Heinrich-Heine-University Düsseldorf; Germany
5. Institute of Pathology, Cytology and Molecular Pathology; Bergisch Gladbach Germany
6. Department of Pathology, Medical Faculty; Heidelberg University Hospital; Heidelberg Germany
7. Mathematical Institute, Heinrich-Heine-University of Düsseldorf; Germany