LGI1 and breast cancer: For example, patients with LE and LGI1 antibodies rarely have a tumor, whereas at least 50% of patients with GABABR antibodies have SCLC,14,15 more than 50% of patients with AMPAR antibodies have thymoma, lung, or breast cancer,16,17 and most (>85%) patients with Hu antibodies have SCLC.8