Although no difference was observed in CD163 levels at the beginning of the culture (Figure 4a and b, D0‐blood monocytes), 41% (18/44) of BC patient monocytes were refractory to M1‐MΦ differentiation since they did not down‐regulate CD163 expression under GM‐CSF/IFN‐γ culture as opposed to HD monocytes (n = 25; 36.1 ± 4.2% all patients vs 16 ± 2.3% HDs; Figure 4a and b). Here, IFNG is linked to breast cancer.