1. Department of Pathology, Cancer Center Amsterdam (CCA) Amsterdam University Medical Centers (Amsterdam UMC), Vrije Universiteit Amsterdam Amsterdam The Netherlands
2. Department of Internal Medicine, Division of Infectious Diseases, Amsterdam Institute for Infection and Immunity (AII) Amsterdam UMC, University of Amsterdam Amsterdam The Netherlands
3. Department of Dermatology Amsterdam UMC, University of Amsterdam Amsterdam The Netherlands
4. Anal Neoplasia Service Homerton University Hospital London UK
5. Department of Dermatology, Venerology and Allergology Helios St. Elisabeth Hospital Oberhausen, University Witten/Herdecke Oberhausen Germany
6. DDL Diagnostic Laboratory Rijswijk The Netherlands
7. Department of Infectious Diseases, STI Outpatient Clinic Public Health Service of Amsterdam (GGD Amsterdam) Amsterdam The Netherlands