[1] Amgen Inc, Thousand Oaks, CA 91320 USA
[2] Amgen Inc, San Francisco, CA USA
[3] Ludwig Maximilians Univ Munchen, Univ Hosp, Dept Internal Med 3, Munich, Germany
[4] Ludwig Maximilians Univ Munchen, Gene Ctr, Lab Translat Canc Immunol, Munich, Germany
[5] Univ Texas MD Anderson Canc Ctr, Houston, TX 77030 USA