[1] Inst Portugues Oncol Francisco Gentil, Dept Dermatol, P-4202452 Oporto, Portugal
[2] Inst Portugues Oncol Francisco Gentil, Dept Gastroenterol, P-4202452 Oporto, Portugal
[3] Inst Portugues Oncol Francisco Gentil, Dept Pathol, P-4202452 Oporto, Portugal
[4] Fac Med, Dept Immunol, P-4202452 Oporto, Portugal
[5] Fac Med, Dept Clin Pharmacol, P-4202452 Oporto, Portugal