Immunosuppressive Drugs and Lung Cancer Risk

Does anyone know if there is a connection between taking immunosuppressive drugs such as Imuran and 6MP and a increased risk of developing lung cancer especially in people that used to smoke?

I mean I always thought that your immune system is what fought back the cancer cells and kept your body clean of them, but if you lower you immune response by taking immunosuppressive drugs doesn't it stand to reason that you are creating an opening for the cancer to take hold?

And then does the choice come down to UC vs Cancer?

Also has anyone else heard about the break through in treating organ transplant patients with stem cells and now they no longer need to take immunosuppressive drugs like Imuran anymore, I wonder if the stem cells would work for UC people as well.

I talked with my cousins, one of whom is an oncologist and the other is a kidney transplant surgeon to ask the same question about lung cancer. I just went on imuran. They both said that imuran Is linked to lymphoma cancers, bit it is not a strong link at that. They didn't feel that my chances of lung cancer would change at sll with the imuran. They also said that the dosage that I am on (100mg) is so low comparative transplant patients, that I should not be concerned. It is not shutting down the immune system, just suppressing it a bit.