Bousquenaud M, et al. - Authors intended to understand the biology behind the observation that tumors in obese patients tend to seed more distant metastases in breast cancer. They ovariectomized C57BL/6 J female mice and fed them either a regular diet (RD) or a high-fat diet (HFD) to generate a postmenopausal diet-induced obesity model to illustrate the effects of the obese microenvironment on metastatic spread. Results demonstrated that tumor cells in the primary tumor, independently of the microenvironment of the secondary site, acquire a pro-metastatic effect of obesity. According to data, transplanting HFD-derived tumor cells in RD mice transfers boosted tumor growth and formation of lung metastasis.