LEP and cancer: In this context, leptin acts as a pro-inflammatory cytokine in the tumor microenvironment, exerting endocrine, paracrine, and autocrine action, inducing the activation of cancer-associated fibroblasts (CAF) and, high levels of MMPs, and promoting cell infiltration to the immune system such as via cancer-associated macrophages (CAM), triggering the secretion of pro-inflammatory and pro-angiogenic cytokines and growth factor [107,108,109].