Breast cancer epithelial cells possess insulin receptors, and experiments with human breast cancer cell lines have demonstrated that the hormone has direct mitogenic activity which is mediated via the phosphatidylinositol-3 kinase and mitogen-activated protein kinase/Akt signaling pathways; insulin is also a cell survival (anti-apoptotic) agent and enhances tumor cell migration and invasive capacity (reviewed by Rose and Vona-Davis, [102]). This evidence concerns the gene WNK2 and breast cancer.