Upregulated IL-18 expression, both in TAMs via activation of NF-κB/NF-κB1 and in breast cancer cells by activation of PI3K-AKT/activating transcription factor 2 (ATF-2) signaling pathways induced by leptin and IL-8 production in M2 macrophages stimulated by leptin, significantly promotes the migration and invasion of breast cancer cells. This evidence concerns the gene LEP and breast cancer.