ESR1 and breast cancer: And breast cancer patients with ER (−) in tumor cells having higher rates of other organs (such as brain, lung, liver) metastasis might relate to the downregulated mammaglobin and lipophilin B, which are located in the 11q13 (33), so as to let 18F-FDG PET/CT play a greater role in finding metastases and improving staging in the low ER expression group.