CCR2 and cancer: Macrophage conditioned media is also capable of inducing expression of CSF-1R and CCR2 by mammary carcinoma cells, indicating that there is a cycle whereby cancer cells induce macrophage proliferation and phenotypic change, and the presence of macrophages leads to cancer cell growth, with both processes occurring, at least partially, through CSF-1R/CCR2 signalling (Fig. 8).