[1] Brunel Univ London, Coll Hlth & Life Sci, Biosci, Uxbridge, Middx, England
[2] Harefield Hosp, Royal Brompton & Harefield NHS Fdn Trust, Div Thorac Surg, London UB9 6JH, England
[3] Royal Cornwall Hosp, Royal Cornwall Hosp NHS Fdn Trust, Obstet & Gynaecol Dept, Truro TR1 3LJ, England
[4] Karolinska Inst, Dept Med, S-17177 Stockholm, Sweden
[5] Sechenov First Moscow State Med Univ, Dept Oncol & Reconstruct Surg, Moscow 119146, Russia