LEP and obesity due to melanocortin 4 receptor deficiency: Our results clearly demonstrated that obesity led to significantly enhanced overall and organ-specific metastatic burden in three in vivo cohorts: (1) nude mice fed a control diet (CD) vs. western diet (WD, 40% fat, diet-induced obesity, or DIO) injected with human OvCa cells; (2) C57Bl/6 mice fed CD vs. WD and injected with syngeneic murine ID8 OvCa cells; and (3) wild-type C57Bl/6 mice vs. B6.Cg-Lepob (leptin mutant, ob/ob mice) injected with ID8 cells.