1. Department of Dermatology, University Hospital Zürich, Zürich, Switzerland;
2. Kempf and Pfaltz, Histological Diagnostics, Research Unit, Zürich, Switzerland;
3. Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands;
4. Department of Dermatology, Hospital 12 de Octubre, Madrid, Spain;
5. Department of Dermatology, Hôpital Saint Louis, Paris, France;
6. Department of Medicine, Divisions of Dermatology and Oncology, Duke University Medical Center, Durham, NC;
7. Department of Dermatology, Stanford Comprehensive Cancer Center, Stanford, CA;
8. Department of Dermatological Sciences, University of Florence, Florence, Italy;
9. Skin Tumour Unit, St Thomas' Hospital, London, United Kingdom;
10. Department of Dermatology, Tel Aviv University, Tel Aviv, Israel;
11. Department of Dermatology, Medical University, Graz, Austria;
12. Department of Dermatology, University of Milano-Bicocca, Istituti di Ricovero e Cura a Carattere Scientifico Ospedale Maggiore di Milano, Milano, Italy;
13. Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY;
14. Peter MacCallum Cancer Centre, East Melbourne, Australia;
15. Department of Dermatology, Northwestern University, Chicago, IL;
16. Department of Dermatology, Hospital Clínico, University of Barcelona, Barcelona, Spain;
17. Department of Dermatology, University of São Paulo, São Paulo, Brazil;
18. Department of Dermatology, The University of Texas M. D. Anderson Cancer Center, Houston, TX;
19. Department of Dermatology and Venereal Diseases, Helsinki University Hospital, Helsinki, Finland;
20. Department of Dermatology, University Hospital Nantes, Nantes, France;
21. Department of Dermatology, University of Vienna Medical School, University of Vienna, Vienna, Austria; and
22. Department of Dermatology, University of Wisconsin, Madison, WI