[1] Univ Calif San Francisco, Helen Diller Comprehens Canc Ctr, San Francisco, CA 94143 USA
[2] Cleveland Clin, Cleveland, OH 44106 USA
[3] Duke Univ, Alliance Stat & Data Ctr, Duke Comprehens Canc Ctr, Durham, NC USA
[4] Univ Vermont, Burlington, VT USA
[5] Georgetown Univ Hosp, Washington, DC 20007 USA