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 of body weight and has effects on metabolic, neuroendocrine, reproductive and hematopoietic systems. Breast cancer has also been associated with obesity and reproductive hormones, especially estradiol. Only a few studies have investigated the relation between plasma leptin and risk of breast cancer and only one study evaluated the effect of tamoxifen on leptin levels in patients with breast cancer.
METHODS: We investigated serum leptin levels in gender-, body mass index (BMI)- and age-matched breast cancer patients and healthy individuals (58 of each).
RESULTS: Serum leptin levels were measured by radioimmunoassay (Human Leptin RIA Kit). Serum leptin levels in the breast cancer patients were significantly 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 control and breast cancer patients. There were no significant differences in BMI and leptin levels between pre- and postmenopausal patients (27.00 +/- 1.39 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 serum leptin level in patients using tamoxifen was significantly higher than that 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.