Macrophage/monocyte chemotactic protein-3 (MCP-3), like other two closely related chemokines (MCP1 and MCP-2), is chemotactic to monocytes, but not to neutrophils. MCP-3 showed 78% sequence homology with MCP-1 and 58% sequence homology with MCP-2. The primary receptor for MCP-3 is D6. MCP-3 also competes with MCP-1 to bind to CCR10, and competes with Rantes and MIP-1? to bind to CCR1. MCP-3 stimulates macrophage to secrete proteases. A variety of cancer cell lines express MCP-3, suggesting a role in tumor invasion and metastasia.