Methodological remarks concerning the recent meta-analysis on vascular endothelial growth factor polymorphism and endometriosis risk

Transmembrane G protein-coupled receptor 30 gene polymorphisms and uterine adenomyosis in Korean women

To compare the genetic distributions of 14G protein-coupled receptor 30 (GPR30) single-nucleotide polymorphisms (SNPs) between women with and without uterine adenomyosis. The study population comprised 69 Korean women. Uterine tissues from the adenomyosis and non-adenomyosis groups were used for DNA extraction. Pre-designed PCR/Sanger or Sequencing Primer and TaqMan^® SNP Genotyping Assays were used for the SNP genotyping of the GPR30 gene. Immunohistochemical staining was performed to confirm the GPR30 expression. Differences in genotype and allele frequencies between the two groups were calculated using Fisher's exact test. The rs3802141 CT genotype was more common in the control group (p = .02), and the rs4266553 CC genotype was more common in the adenomyosis group (p = .02). The C allele of the SNP rs4266553 was more common in the adenomyosis group (p = .02). GPR30 expression was confirmed in 69 individuals in both groups. GPR30 gene polymorphism is presumed to affect the risk of adenomyosis with limited sample size. Further large-scale study is needed to explain the genetic influence of GPR30 gene polymorphism.

The association between vascular endothelial growth factor (VEGF) +405G>C genetic polymorphism and endometriosis

The vascular endothelial growth factor (VEGF) is one of the most important candidate genes for the development of endometriosis, and VEGF genetic polymorphisms might be potentially associated with endometriosis risk. However, the results still remain controversial. The objective of this study aimed to perform a comprehensive meta-analysis to explore a better understanding of the effects of VEGF +405G>C genetic polymorphism on the risk of endometriosis. A total of eleven eligible studies were eventually identified in this meta-analysis, including 2829 endometriosis cases and 2947 controls. In the overall analysis, no significant association between the VEGF +405G>C genetic polymorphism and the risk of endometriosis was detected in all genetic models (for homozygote comparison [CC versus vs. GG]: OR = 1.21, 95% CI 0.67-2.19, P = 0.537; for heterozygote comparison [CG vs. GG]: OR = 1.16, 95% CI 0.86-1.56, P = 0.348; for dominant comparison CC/CG vs. GG: OR = 1.10, 95% CI 0.93-1.30, P = 0.263; for recessive comparison [CC vs. CG/GG]: OR = 1.03, 95% CI 0.73-1.47, P = 0.857; allele comparison [C vs. G]: OR = 0.99, 95% CI 0.70-1.40, P = 0.962). In the subgroup analysis by ethnicities, there was no significant association between VEGF +405G>C genetic polymorphism and endometriosis risk in Asians and/or Caucasians under all genetic models (all P-values >0.05). No publication bias was observed in this study. This meta-analysis supports that the VEGF +405G>C genetic polymorphism is not significant associated with the risk of endometriosis.