Cancer and autoimmunity are “often thought of as being at opposite ends of the immune response,” Ana Anderson told her audience at a joint meeting of the NIH’s Office of Autoimmune Disease Research and Office of Research in Women’s Health earlier this month. Cancer, that line of reasoning goes, arises when the immune system is not good enough at recognizing harmful autoantigens. Autoimmunity arises when it is hypervigilant, mistaking harmless autoantigens for problematic ones and going on the attack.