作者单位:Univ Iowa, Internal Med, Iowa City, IA USA[1]Genentech Inc, San Francisco, CA 94080 USA[2]Emory Univ, Winship Canc Inst, Atlanta, GA 30322 USA[3]Washington Univ, Siteman Canc Ctr, St Louis, MO USA[4]Sarah Cannon Res Inst, Nashville, TN USA[5]Univ Rochester, Med Ctr, James Wilmot Canc Ctr, Rochester, NY 14642 USA[6]