Genetic polymorphism in HLA-G 3'UTR 14-bp ins/del and risk of cancer: a meta-analysis of case-control study.

Accumulating evidence has suggested that the human leucocyte antigen-G (HLA-G) 14 bp ins/del polymorphism might be related to cancer susceptibility. However, epidemiologic findings have been inconsistent. Therefore, we performed a meta-analysis of case-control study to derive a more precise estimation of this association. Electronic databases were searched to identify all eligible studies of HLA-G 14 bp ins/del polymorphism and cancer risk. Odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated to evaluate the strength of the association in fixed-effects model or random-effects model according to heterogeneity. Publication bias, sensitivity analysis and subgroup analyses based on cancer type, ethnicity, source of controls and sample size were also performed. A total of 14 case-control studies, involving 2,757 cases and 3,972 controls, were included in the present meta-analysis. The pooled analysis showed that there is no significant relationship between the HLA-G 14 bp ins/del polymorphism and cancer susceptibility under the genetic models (for the allele model del vs. ins: OR 1.13, 95 % CI 1.00-1.27; for the homozygote comparison model del/del vs. ins/ins: OR 1.22, 95 % CI 0.95-1.56; for the dominant model del/del + ins/del vs. ins/ins: OR 1.15, 95 % CI 0.94-1.42; for recessive model del/del vs. ins/del + ins/ins: OR 1.13, 95 % CI 0.96-1.34; respectively). Subgroup analyses indicated significant association among breast cancer, population based control and the large sample size group in some genetic models. Our investigations demonstrate that genotypes for the HLA-G 14 bp ins/del polymorphism may be not associated with overall cancer risk. In a subgroup meta-analysis, however, HLA-G 14-bp ins/del polymorphism might contribute to breast cancer susceptibility.