[1] Int Agcy Res Canc, Unit Field & Intervent Studies, F-69372 Lyon 08, France
[2] Vrije Univ Amsterdam, Med Ctr, Dept Pathol, Amsterdam, Netherlands
[3] Inst Nacl Cancerol, Div Invest, Bogota, Colombia
[4] Free Univ Amsterdam, Fac Med, Med Ctr, Immunogenet Lab, Amsterdam, Netherlands