The production of proangiogenic proteins such as VEGF, MCP-1, leptin, and TNF-α, by macrophages and adipocytes [26,27,34] and the increased vascular network demonstrated in adipose tissue surrounding experimental mammary tumors is consistent with the described interactions between obesity, inflammation and insulin resistance in breast cancer development. This evidence concerns the gene CCL2 and obesity due to melanocortin 4 receptor deficiency.