title: A meta-analysis of hypoxia inducible factor 1-alpha (HIF1A) gene polymorphisms: association with cancers.
abstract: BACKGROUND
  Hypoxia inducible factor 1-alpha (HIF1A) is a transcription factor that plays important role in regulating cascade of reactions. In this study, the effect of rs11549465 (1772 C/T) and rs11549467 (1790 G/A) polymorphisms of HIF1A gene and its association with cancers were investigated through meta-analysis.
  
  
  METHODS
  Meta-analysis of genome wide association studies of HIF1A 1772 C/T polymorphism were conducted on 22 case-control studies of sample size 19024 and for 1790 G/A polymorphism 19 case-control studies were included with sample size 10654. Genotype and allelic frequency compared between cases and controls together with further subgroup analyses were carried out by cancer type and ethnicity.
  
  
  RESULTS
  Meta-analysis from this study indicated that HIF1A 1772 C/T polymorphism is significantly associated with overall cancer risk. T allele and genotype TT are significantly associated with increasing overall cancer risk; odds ratios (OR) dominant model [TT + CT vs. CC: OR 1.30, 95 % CI (1.06-1.59), p-value: 0.0115], and T allele vs. C allele: OR 1.32, 95 % CI (1.07-1.63), p-value: 0.0098. Also, HIF1A 1790 G/A polymorphism, analyses showed that A allele and genotype AA are significantly associated with increasing overall cancer risk; odds ratios (OR) homozygote comparison [AA vs. GG: OR 5.10, 95 % CI (3.12-8.33), p-value: <0.0001], heterozygote comparison [GA vs. GG: OR 1.74, 95 % CI (1.20-2.52), p-value: 0.0033], dominant model [AA + GA vs. GG: OR 1.82, 95 % CI (1.26-2.62), p-value: 0.0014], recessive model [AA vs. GA + GG: OR 3.79, 95 % CI (2.34-6.15), p-value: <0.0001] and A allele vs. G allele: OR 1.82, 95 % CI (1.31-2.52), p-value: 0.0003.
  
  
  CONCLUSIONS
  In detail meta-analysis indicated that both the polymorphisms 1772 C/T and 1790 G/A are significantly associated with overall cancer risk. The subgroup analyses showed that lung cancer is significantly associated with both polymorphisms. Although the 1772 C/T polymorphism is significantly associated with decreasing risk of renal cell carcinoma but the 1790 G/A polymorphism has shown to significantly increase the cancer risk in both Caucasian and Asian population. Thus, HIF1A could be a useful prognostic marker for cancers early predisposition.
authors.affiliation: Department of Statistics, Biostatistics & Informatics, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.forename: Md T
authors.initials: MT
authors.lastname: Anam
authors.affiliation: Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.forename: Alokta
authors.initials: A
authors.lastname: Ishika
authors.affiliation: Department of Statistics, Biostatistics & Informatics, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.forename: Md B
authors.initials: MB
authors.lastname: Hossain
authors.affiliation: Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, 1000 Bangladesh.
authors.lastname: Jesmin
keywords: Cancer; Genome wide association studies; HIF1A; Meta-analysis