Correlation of Q223R and K109R polymorphisms in leptin receptor gene with susceptibility of breast cancer: A systematic review and meta-analysis.

BACKGROUND: Increasing evidence has suggested a strong association of Q223R (rs1137101) and K109R (rs1137100) polymorphisms in leptin receptor (LEPR) gene with susceptibility of breast cancer (BC), but inconsistent results were obtained. To provide a quantitative assessment of this association, a systematic review and meta-analysis was performed.

METHODS: A literature search of PubMed, EMBASE, Google Scholar and the Chinese Nationlal Knowledge Infrastructure was collected. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated.

RESULTS: A total of 20 case-control studies for Q223R polymorphism and 8 case-control studies for K109R polymorphism were included. Significant association between Q223R polymorphism and BC risk was not found in total, Asian or Caucasian population, but in African population: allelic model, OR = 0.72, 95% CI = 0.60-0.86, p < 0.001; recessive model, OR = 0.67, 95%CI = 0.52-0.87, P = 0.003; dominant model, OR = 1.58, 95% CI = 1.15-2.17, p = 0.004; homozygous model, OR = 0.51, 95% CI = 0.36-0.78, p < 0.001. Significant association between K109R polymorphism and BC risk was not found in total or Caucasian population, but in Asian population: dominant model, OR = 0.24, 95% CI = 0.07-0.84, p = 0.03; heterozygous model, OR = 1.87, 95% CI = 1.07-3.26, p = 0.03.Conclusion: The available evidence suggests that Q223R polymorphism may be significantly associated with BC risk in African population. K109R polymorphism may be significantly associated with BC risk in Asian population.