Synaptonemal Complex Protein 1 (SCP1) is a novel tumor antigen that belongs to the growing family of cancer/testis antigens (CTAs). CTAs are theoretically ideal targets for tumor immunotherapy. Unlike most auto-antigens, CTAs are highly immunogenic, even in the autologous cancer-bearing patients. Furthermore, because of their very restricted normal tissue expression, immunotherapy targeting CTAs is expected to be more specific and less toxic.