Individuals with either of two genetic variations that lead to high serum levels of the cytokine leptin and to overexpression of leptin in fatty tissue, are more at risk of developing breast cancer than others. A study published in the open access journal BMC Cancer suggests that individuals with a specific genetic variation (polymorphism) in the gene LEP that encodes for leptin, or a polymorphism in the gene LEPR, encoding for its receptor, have an increased risk of breast cancer. This contradicts previous results that showed no link between the polymorphism in LEPR and the risk of breast cancer. Both polymorphisms could be used as markers to identify people at risk of breast cancer. As they are both associated with a shorter survival time they could potentially serve as predictors of prognosis.
Kaouther Snoussi, from the Universite de Monastir, Monastir, Tunisia and colleagues from other institutions in Tunisia and Scripps-Florida, USA, matched 308 patients diagnosed with breast cancer with 222 healthy individuals. The authors genotyped both patients and control individuals for a specific polymorphism in either LEP or LEPR.
Results from this study show that individuals with the LEP polymorphism had a higher risk of developing breast cancer than individuals who do not have it. The risk increased for individuals with two copies of the polymorphism (homozygote) and these people had a threefold higher risk of developing breast cancer than individuals who do not have the polymorphism at all. The frequency of individuals with the LEPR polymorphism was significantly higher in the group of patients than in the group of controls. The LEP polymorphism was also associated with a large tumour size at diagnosis and decreased disease-free survival, while the LEPR polymorphism was associated with a shorter overall survival time. |
