Association Between the (GT)n Polymorphism of the HO-1 Gene Promoter Region and Cancer Risk: a Meta-analysis

Background: Several studies have previously focused on associations between the (GT)n repeat polymorphismof the heme oxygenase-1 (HO-1) gene promoter region and risk of cancers, but results are complex. We conductedthe present meta-analysis to integrate relevant findings and evaluate the association between HO-1 (GT)nrepeat polymorphism and cancer susceptibility. Materials and
Methods: Published literature was retrievedfrom the PubMed/MEDLINE, EMBASE and ISI Web of Science databases before November 2013. For allalleles and genotypes, odds ratios were pooled to assess the strength of the associations using either fixed-effectsor random-effects models according to heterogeneity. Subgroup analysis was conducted according to ethnicityand histopathology.
Results: A total of 10 studies involving 2,367 cases and 2,870 controls were identified. Theresults showed there was no association between HO-1 (GT)n repeat polymorphism and the cancer risk both atthe allelic and genotypic level. However, in the stratified analysis, we observed an increased risk of squamouscell carcinoma in persons carrying the LL genotype and the LL+LS genotype as compared with those carryingthe SS genotype. When the LS and SS genotypes were combined, the odds ratio for squamous cell carcinoma inLL-genotype carriers, were also significantly increased. No publication bias was observed.
Conclusions: The LLgenotype and L-allele carrying genotypes (LL+LS) of HO-1 (GT)n repeat polymorphism are potential geneticfactors for developing squamous cell carcinoma. More large and well-designed studies are required for furthervalidations.