Previous reports have demonstrated leptin’s ability to promote many cancer signaling pathways including phosphatidylinositol 3 – kinase protein kinase B (PI3K/AKT), mitogen-activated protein kinase (MAPK), and Janus Kinase 2-Signal transducer and activator of transcription 3 (JAK2/STAT3) pathways that promote tumorigenesis and metastasis [16, 37–41]. Here, STAT3 is linked to cancer.