Systemic lupus erythematosus (SLE), commonly known as lupus, is an autoimmune disease in which the body's immune system attacks healthy tissue such as the skin, joints, kidneys and the brain, leading to inflammation and lesions. The disease affects about 1 in 2000 Canadians, particularly women. Previous research has suggested that lupus patients have an increased risk of developing cancer, particularly lymphoma.  Lymphoma is a type of blood cancer that occurs when cells called lymphocytes, which usually help protect the body from infection and disease, begin growing and multiplying uncontrollably leading to tumor growth.