To strictly address the importance of astrocyte-secreted MCP-1 in attracting melanoma cells and promoting their growth, we compared the ability of melanoma cells to migrate in coculture toward astrocytes, microglia, or endothelial cells (known to be the alternative sources of MCP-1 in the brain), following neutralization of MCP-1 secretion. This evidence concerns the gene CCL2 and melanoma.