Effects of tamoxifen on the serum leptin level in patients with breast cancer

Background: Leptin is a peptide hormone that has a role in the regulation o f body weight and has effects on metabolic, neuroendocrine, reproductive an d hematopoietic systems. Breast cancer has also been associated with obesit y and reproductive hormones, especially estradiol. Only a few studies have investigated the relation between plasma leptin and risk of breast cancer a nd only one study evaluated the effect of tamoxifen on leptin levels in pat ients with breast cancer. Methods: We investigated serum leptin levels in gender-, body mass index (B MI)- and age-matched breast cancer patients and healthy individuals (58 of each). Results: Serum leptin levels were measured by radioimmunoassay (Human Lepti n RIA Kit). Serum leptin levels in the breast cancer patients were signific antly higher than those in the control group (27.00 versus 17.65 ng/ml, p = 0.019). There were no differences with respect to BMI and age between cont rol and breast cancer patients. There were no significant differences in BM I and leptin levels between pre- and postmenopausal patients (27.00 +/- 1.3 9 and 27.19 +/- 0.81 kg/m(2), 26.81 +/- 6.25 and 27.06 +/- 2.98 ng/ml) (p > 0.05). We found no difference in serum leptin level between early and late stages of patients (22.38 versus 31.30 ng/ml, p = 0.086). However, the ser um leptin level in patients using tamoxifen was significantly higher than t hat of patients not using tamoxifen (32.71 and 19.39 ng/ml, respectively p = 0.009). There was no correlation between CA 15-3 and leptin level (r = 0. 069, p = 0.610). Conclusion: High serum leptin levels seen in breast cancer patients are not related to stage of the disease or to cancer itself but may be associated with the use of tamoxifen.