Furthermore, In mouse model of mammary tumor, using a leptin receptor antagonist [28]revealed that leptin signaling promotes the growth of some types of mammary tumors and increases the expression of proliferating cell nuclear antigen, cyclin D1, vascular endothelial growth factor (VEGF) and its receptor type two (VEGF-R2) [30,31]. The gene discussed is LEPR; the disease is breast cancer.