Effects of leptin and leptin receptor gene polymorphisms on lung cancer

Leptin (LEP), an adipocyte-derived cytokine, has been reported to participate in carcinogenesis. Elevated levels of systemic and pulmonary LEP are associated with diseases related to lung injury and lung cancer. The purpose of the present study was to investigate if the LEP and leptin receptor (LEPR) gene polymorphisms are associated with lung cancer in a cohort of Turkish population. One hundred and sixty-two lung cancer patients and 130 healthy controls were included in the study. The genotypes of LEP gene −2548G > A and LEPR gene Q223R polymorphisms were determined using polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP) analysis. The genotype frequencies of LEP −2548G > A polymorphism showed statistically significant differences between lung cancer patients and controls (p = 0.007). GA + AA genotypes and A allele of LEP −2548G > A polymorphism was found to be susceptibility factors for lung cancer (p = 0.003, odds ratio (OR) 2.32, 95 % confidence interval (CI) 1.32–4.10; p = 0.003, OR 1.65, 95 % CI 1.18–2.29, respectively). The genotype and allele frequencies of LEPR Q223R polymorphism did not show any statistically significant differences between lung cancer patients and controls (p = 0.782 and p = 0.762, respectively). Although AA–QQ and AA–QR combined genotypes of LEP −2548G > A-LEPR Q223R loci were significantly higher in lung cancer patients (p = 0.020 and p = 0.047, respectively), GG–QQ, GG–QR, and AA–RR combined genotypes were significantly higher in control group. As a result, susceptibility effects of LEP −2548G > A polymorphism alone or in combination with LEPR Q223R polymorphism on lung cancer were observed. Further studies are necessary to prove the association of LEP and LEPR gene polymorphisms with lung cancer.