CD47 and breast carcinoma: E0771 cells lack surface CXCR4, a widely expressed chemokine receptor involved in breast cancer survival and metastasis (43), but retains high surface levels of the “don’t eat me signal” CD47 (44), implicated in the escape of CTC from systemic macrophage and neutrophil-mediated phagocytosis (44) (Supplementary Figure 3).