High Leptin Levels Increase Breast Cancer Risk

Researchers have found that leptin, an adipocyte-derived cytokine associated with weight gain, promotes breast cancer cell growth, which may help to explain the association between weight gain and increased breast cancer risk. Their finding was reported in the November 20, 2002, issue of the Journal of the National Cancer Institute.

To investigate whether leptin was associated with breast cancer, investigators from the University of Minnesota (Austin, USA; www.umn.edu) and colleagues determined the expression of leptin's receptor OB-Rb in human breast epithelial HBL100 cells and human breast carcinoma-derived T-47D cells, determined whether leptin influenced the proliferation of these cells, and evaluated the structure of mammary tissue in genetically obese leptin-deficient and leptin receptor-deficient mice.

Results showed that, in the presence of leptin, the number of cancerous breast cells increased 150% as compared to 50% for normal breast cells. In an experiment designed to assess the cells' ability to form tumors, it was found that only the breast cancer cell line exposed to leptin responded and proliferated. Obese leptin-deficient and leptin receptor-deficient mice had minimal epithelial development in the mature mammary gland compared with their lean counterparts.

"These findings may explain why weight gain, which is accompanied by higher-than expected leptin concentrations, also has been associated with increased breast cancer risk,” explained senior author Dr. Margot P. Cleary of the University of Minnesota's Hormel Institute. "Preventive measures need to be taken to control these deadly diseases.”



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