Affiliation: | Department of Dermatology, Churchill Hospital, Oxford. OX3 7LJ, UK,;Department of Cellular Pathology, The John Radcliffe Hospital, Oxford OX3 9DU, UK.; Corresponding author, Department of Dermatology, Churchill Hospital, Headington, Oxford OX3 7LJ, UK, tel. +44 (0)1865 228232;fax +44 (0)1865 228240. |