In SCID (severe combined immunodeficiency)/beige mice implanted either with ER-positive MCF-7 breast cancer cells: (i) alone, (ii) mixed with obese adipose stromal/stem cells (obASCs) isolated from obese patients, or (iii) mixed with obASCs silenced for leptin gene (leptin shRNA obASCs), a reduction in tumor growth and a decreased number of lung and liver metastases were found compared to those not silenced for the leptin gene [177]. Here, LEP is linked to severe combined immunodeficiency.