[1] Imperial Coll London, Imperial Coll, Sch Med, London W2 1NY, England
[2] Royal Free London NHS Fdn Trust, Dept Cellular Pathol, London, England
[3] Imperial Coll Healthcare Trust, Dept Cellular Pathol, London, England
[4] St Marys Hosp, Dept Cellular Pathol, London W2 1NY, England