There is a genetic connection in some forms of colon cancer, though I believe a better indicator is if you ahve had any first-degree relatives develop colon cancer at early ages. However, lymphoma and leukemia are different from colon cancer and probably do not have the same genetic setups, if any. I do know that lymphoma can run in families, though again I suspect thre medical histories are better indicators than genes. Most of the research I have seen shows very, very small probabilities of any cancers related to the primary Crohn's treatments. However, where such numbers exist, they mostly relate tothe top-doen treatments, not the bottom-ups. And of course an identified factor in the development of lymphoma in Crohn's patients, as well as colon cancer, is uncontrolled long term inflammation from the disease itself. So treat and run a tiny risk or don't treat, be less comfortable and also run a small but identifiable risk. Hard call. Most patients opt for better quality of life through treatment.