Aside from polarization modulation effect of CSCs on macrophages, CSCs could also adapt an anti-phagocytosis strategy through upregulating cell surface CD47 expression and bind with signal regulatory protein alpha (SIRPα) on macrophages to phosphorylate the ITIM motif, conveying the “do not eat me” signal to escape elimination pressure from tumor-suppressive macrophages (Figure 2) [104]. Here, CD47 is linked to neoplasm.