Based on the immunohistochemistry (IHC) staining scores (refer to Methods), the rate of high expression (+ to +++) of COPS5 protein is significantly elevated in tamoxifen-refractory breast tumours (86.7%, 26/30) compared with untreated breast tumours (25.8%, 8/31) (Fig. 1d,e, Supplementary Table 2). The gene discussed is COPS5; the disease is breast neoplasm.