LEP and breast cancer: Indeed, leptin has been shown to regulate neoangiogenesis; enhance endothelial cell growth [19, 20]; suppress apoptosis through a Bcl-2-dependent mechanism [73]; act as a mitogen, transforming factor, or migration factor for many different cell types, including smooth muscle cells [74], normal and neoplastic colon cells [75, 76], and normal and malignant mammary epithelial cells [77, 78]; and induce the metastasis of breast cancer, possibly in an autocrine manner [79].