[1] Inst Gustave Roussy, Dept Surg, Sarcoma Unit, F-94805 Villejuif, France
[2] Assistance Publ Hop Paris, Hop Bichat Claude Bernard, Gastrointestinal Unit, Paris, France
[3] Inst Gustave Roussy, Dept Pathol, F-94805 Villejuif, France
[4] Inst Gustave Roussy, Dept Med, F-94805 Villejuif, France