Interestingly, a recent study using a mouse model of breast cancer showed that TAMs are recruited via CCR2 signaling to primary tumors where they induce CXCR4 expression in response to tumor-derived TGFβ and then migrate toward the blood vessel via CXCL12 to promote intravasation of cancer cells (83). The gene discussed is CXCR4; the disease is breast cancer.