Nakayama et al. found in axillary lymph node metastatic tissues of BC that, unlike CD44 which is highly expressed in all CSCs, HMGA1 is only highly expressed in certain specific CSC subgroups, and based on this, Nakayama et al. [13] named it the "HMGA1 high-tumor stem cell subgroup". The gene discussed is HMGA1; the disease is neoplasm.