Fig. 1

Inhibitor of differentiation 4 (ID4) protein and macrophage marker CD68 are significantly associated in triple-negative breast cancer (TNBC). a and b A series of 62 TNBC samples was stained for ID4 protein and for the macrophage marker CD68. ID4 protein expression was considered positive when we observed an immunoreaction in the cytoplasm and/or nucleus. Staining intensity was evaluated as follows: 0 negative, 1+ mild, 2+ moderate, 3+ strong. ID4 was considered overexpressed when more than 10% of neoplastic cells presented a strong immunoreaction. CD68 staining was scored as the infiltration density and was evaluated as follows: 0 absent, 1+ mild, 2+ moderate, 3+ dense. a Fisher’s exact test demonstrated that high ID4 and CD68 expression are significantly associated (P = 0.028). b Representative images of TNBC showing high or low protein levels of ID4 or CD68. c–f Predictive power of ID4 messenger RNA expression for distant metastasis-free survival (DMFS) (N = 232) was evaluated by Kaplan-Meier analysis in basal-like breast cancer (BLBC) showing high or low CD68 (c and d) or macrophage signature (MacSig) (e and f) levels. Macrophage signature is composed of eight widely used markers for the mononuclear phagocyte system (CD14, CD105, CD11b, CD68, CD93, CD33, IL4R, and CD163 [37])