CCL2 and breast cancer: CCL2, also known as MCP-1, is a classical chemokine whose receptor is CCR2, and the CCL2–CCR2 axis has already been found to be involved in inflammatory processes, including immune cell chemoattraction, differentiation, and proliferation (37), and growth and metastasis in several cancer types, such as breast cancer (38) and PCa (27, 39).