In the study by Linde et al. CD206hi intra-epithelial macrophages in the very early stage of mammary intra-epithelial neoplasia in mice, which is similar to ductal carcinoma in situ (DCIS) in humans, were shown to respond to tumor secreted chemokine ligand 2 (CCL-2), which in turn stimulates macrophages to produce Wnt-1, leading to disruption of E-cadherin junctions between early cancer cells and propelling lung dissemination. Here, WNT1 is linked to ductal breast carcinoma in situ.