[1] Univ Texas MD Anderson Canc Ctr, Dept Canc Biol, Houston, TX 77030 USA
[2] Johns Hopkins Med Inst, Baltimore, MD 21205 USA
[3] Univ Texas MD Anderson Canc Ctr, Dept Surg Oncol, Houston, TX 77030 USA
[4] Univ Texas MD Anderson Canc Ctr, Dept Pathol, Houston, TX 77030 USA
[5] Newcastle Univ, Dept Pathol, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[6] Univ Texas MD Anderson Canc Ctr, Dept GI Med Oncol, Houston, TX 77030 USA