ER−PR− and ER+PR− groups displayed poor prognostic features as compared to the ER+PR+ subtype, i.e., higher grade (p < 0.001) and Ki67 proliferation index (AKW p = 0.011, post-hoc p = 0.062 ER+PR+ vs. ER+PR− and p = 0.086 ER+PR+ vs. ER−PR−), larger tumor size (AKW p < 0.001, post-hoc p = 0.297 ER+PR+ vs. ER+PR− and p = 0.007 ER+PR+ vs. ER−PR−), and more frequent HER2 amplification (p < 0.001) (Table 1). The gene discussed is ERBB2; the disease is neoplasm.