[1] MIT, Dept Biol, David H Koch Inst Integrat Canc Res, Cambridge, MA 02139 USA
[2] Harvard Med Sch, Harvard MIT MD PhD Program, Boston, MA 02115 USA
[3] Massachusetts Gen Hosp, Dept Pathol, Boston, MA 02114 USA
[4] Duke Univ, Dept Med, Div Gastroenterol, Durham, NC USA
[5] Duke Univ, Dept Pharmacol & Canc Biol, Durham, NC USA