Purpose: The purpose of this systematic meta-analysis was to evaluate the association between leptin (LEP) and leptin receptor (LEPR) gene polymorphisms and non-Hodgkin lymphoma (NHL) risk.
Methods: All studies published up to July 2014 on the association between LEP and LEPR polymorphisms and NHL risk were identified by searching PubMed, Web of Science, EMBASE, and Google Scholar. Odds ratios (ORs) with 95% confidence intervals (CIs) for LEP and LEPR polymorphisms and NHL were calculated with fixed-effects and random-effects models.
Results: LEP G2528A polymorphism was associated with increased, yet not statistically significant risk of NHL (homozygote comparison, OR=1.27, 95% CI=1.01-1.60, p=0.63; heterozygote comparison, OR=1.13, 95% CI=0.86-1.49, p=0.14; dominant model, OR=1.18, 95% CI=0.99-1.41, p=0.21; recessive model, OR=1.18, 95% CI=0.97-1.43, p=0.78; additive model, OR=1.14, 95% CI=1.01-1.28, p=0.52). Significant decrease of NHL risk was found in LEP A19G polymorphism, while no links were detected with the LEPR polymorphisms studied. In subgroup analysis, the pooled results showed that LEP A19G polymorphism was associated with decreased risk of follicular lymphoma (FL) (homozygote comparison, OR=0.56, 95% CI=0.37-0.85, p=0.69). However, no evidence of a significant association was observed in diffuse large B-cell lymphoma (DLBCL) for variant genotypes of all single nucleotide polymorphisms (SNPs).
Conclusions: LEP G2548A polymorphism contributes to NHL susceptibility. Also, our results provide evidence that LEP A19G polymorphism is associated with decreased risk of NHL, especially in FL. Further large-scale and well-designed studies are needed to confirm this association.