CCL18, which is derived from tumor-associated macrophages (TAMs), via its receptor, PITPNM3, recruits inflammatory monocytes and Tregs to the breast cancer TME and induces the invasion and metastasis of breast cancer through the phosphoinositide-3-kinase (PI3K)/anti-apoptotic kinase (Akt)/GSK3β/Snail pathway [93,94]. The gene discussed is PITPNM3; the disease is breast cancer.