1. Department of Dermatology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
2. Program of Glyco-Immunology and Oncology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA.
3. Department of Surgery, University Hospital Mannheim, Heidelberg University, 68167 Mannheim, Germany.
4. Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander-University (FAU), 91054 Erlangen, Germany.
5. Department of Dermatology, University Hospital Bonn, 53127 Bonn, Germany.
6. Department of Dermatology and Venerology, Johannes Kepler University, 4020 Linz, Austria.
7. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
8. Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
9. Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA.
10. Merkel Cell Carcinoma Center of Excellence, Dana-Farber/Brigham and Women’s Hospital Cancer Center, Boston, MA 02115, USA.
11. Department of Dermatology, Vienna Healthcare Group, 1130 Vienna, Austria.
12. Faculty of Medicine, Sigmund Freud University Vienna, 1020 Vienna, Austria.
13. Department of Dermatology and Allergy, School of Medicine, Technical University of Munich, 81675 Munich, Germany.
14. Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA.