Effect of leptin receptor Q223R polymorphism on breast cancer risk

OBJECTIVES Leptin receptor (LEPR) is a member of the class I cytokine receptor super-family that is known implicated in the initiation and progression of breast cancer. We have investigated the effect of Q223R polymorphism on the breast cancer susceptibly in a sample of Iranian subjects. MATERIALS AND METHODS We utilized a polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method to investigate the association of LEPR Q223R polymorphism with breast cancer risk in a case control study consisting of 100 breast cancer cases and 100 controls without breast cancer. Serum levels of leptin and soluble leptin receptor (sOB-R) were measured by ELISA method. RESULTS The genotype (QQ, QR, and RR) distributions were 25, 56, and 19 % in breast cancer cases and 54, 40, and 6% in controls, respectively. The frequency of 223 RR genotype was significantly elevated in breast cancer cases as compared to controls (χ(2)= 20.072, P<0.001). Similar significance differences were also found in allele frequencies for Q and R between two groups (χ(2)= 19.027, P< 0.001). Additionally, there were significant association between Q223R genotypes and breast cancer risk; homozygotes for RR genotype (OR= 6.840; 95% confidence interval [CI] = 2.434-19.218), heterozygotes for QR (OR=3.024; 95% CI = 1.620-5.644, P = 0.001), and QR+RR genotype (OR= 3.522; 95% CI = 1.934-6.414, P < 0.001), respectively. CONCLUSION Our results showed that the LEPR Q223R polymorphism is associated with increased breast cancer risk as well as tumor grade in a sample of Iranian subjects.