1. Department of Twin Research and Genetic Epidemiology; King's College London; St Thomas' Campus, Westminster Bridge Road London SE1 7EH U.K
2. Section of Dermatology; Department of Medical Sciences; University of Turin; Torino Italy
3. Imperial College London; London U.K
4. Department of Dermatology; London North West Healthcare NHS Trust; London U.K
5. Unit of Cancer Epidemiology - CERMS; Department of Medical Sciences; University of Turin; Torino Italy
6. Mount Vernon Cancer Network; West Herts NHS Trust; Herts U.K
7. Department of Dermatology; West Herts NHS Trust; Herts U.K