[1] F Hoffmann La Roche Ltd, Basel, Switzerland
[2] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA
[3] Univ Complutense, Hosp Gregorio Maranon, Madrid, Spain
[4] Genentech Inc, San Francisco, CA USA
[5] Univ Southern Calif, Keck Sch Med, Norris Comprehens Canc Ctr, Los Angeles, CA 90033 USA