[1] Univ Calif San Francisco, Dept Med, San Francisco, CA USA
[2] Canc Prevent Inst Calif, Fremont, CA USA
[3] Stanford Canc Ctr, Dept Med, Stanford, CA USA
[4] Univ Calif San Francisco, Dept Med, Helen Diller Family Comprehens Canc Ctr, San Francisco, CA USA
[5] Univ Calif San Francisco, Dept Epidemiol & Biostat, San Francisco, CA 94143 USA
[6] San Francisco VA Med Ctr, Dept Med, Div Hematol & Oncol, San Francisco, CA 94121 USA