For example, two of the biomarkers (MAGE4 and XAGE4) are highly expressed only in a subset of triple-negative breast cancer patients and of HER2 + /ER− patients (Fig. 1H); interestingly, one of the two (MAGE4) has been previously reported in the literature as overexpressed in such patients by proteomic profiling44. The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.