Furthermore, when we compared the OS among four different molecular subtypes of all 280 cases of breast cancer patients, highly infiltrated eMDSCs strongly correlated with poor patient outcome in luminal A subtype (p < 0.0001, Figure 2E), rather than in other subtypes such as luminal B, HER2 overexpression and Basal-like (p = 0.2465, p = 0.7607, p = 0.4780, Figures 2F–H). Here, ERBB2 is linked to breast cancer.