Stimulated M2 polarization. Moreover, human explant mammary gland cultures treated with rSFRP1 show a marked reduction in the human M2 marker, CD163. CD163 is a monocyte/macrophage-restricted scavenge receptor [47] and the mechanism by which rSFRP1 reduces CD163 expression may be due in part to repression of Wnt signaling because Bergenfelz et al. show that breast cancer CD163+ TAMs correlate with