[1] St Johns Inst Dermatol, London, England
[2] Univ London Imperial Coll Sci Technol & Med, London, England
[3] Royal Marsden Hosp, London SW3 6JJ, England
[4] UCL, London, England
[5] Spanish Natl Canc Inst, Madrid, Spain
[6] Univ Zurich Hosp, Zurich, Switzerland