Increased risk of lymphoma among inflammatory bowel disease patients treated with azathioprine and 6-mercaptopurine
A Kandiel, A G Fraser, B I Korelitz, C Brensinger, and J D Lewis

Competing interest: JDL has received research support and has served as a consultant for Wyeth and GlaxoSmithKline. BIK has received research funding from Centocor. AK, AGF, and CB report no potential conflicts of interest.