Table 2.

Summary of Ggenetic polymorphism studies with significant differences

Reference	Sample size	Involved genes	Population	Summary
Lee, et al., 2014[25]	Case: 673	CDKN2B-AS gene	Korean	The CC genotype of the rs10965235 SNP in the CDKN2B-AS gene and the GG genotype of the rs16826658 SNP near the WNT4 gene were significantly associated with endometriosis in Korean population
	Control: 500
		WNT4 gene
Cho et al., 2013[26]	Case: 201	MMP-2 gene	Korean	In MMP-2, G/A haplotype of 9082A>G and 9152A>G in intron 2 was associated with a reduced risk of endometriosis (OR 0.7, 95% CI 0.5-1.0, P=0.04)
	Control: 183	TIMP-2 gene
				In TIMP-2, the CC genotype of 42196430T>C and C/C haplotype of 42196041G>C/42196430T>C in the promoter region showed an increased risk of endometriosis (OR 3.0, 95% CI 1.2-8.0, P=0.02; OR 1.6, 95% CI 1.1-2.4, P=0.02)
				In TIMP-2, the CC genotype of 42183387T>C and the C/G/C haplotype of 42175617C>T/42181597G>A/42183387T>C in intron 1 were associated with a reduced risk (OR 0.5, 95% CI 0.3-0.97, P=0.04; OR 0.6, 95% CI 0.4-0.95, P=0.03)
Wang et al., 2012[27]	Case: 300	HSD17B3	Taiwanese	These 4 nsSNPs reside ((rs6165, rs6166, rs2066479, rs700519)) in 3 genes related to estrogen synthesis (HSD17B3, FSHR, and CYP19) increases endogenous production of more estrogens may be more strongly associated with the risk of endometriosis
	Control: 337	FSHR
		CYP19
Kim et al., 2012[28]	Case: 268	COX-2 gene	Korean	The C allele for -765G/C of the COX-2 gene was associated with significantly lower risk of advanced-stage endometriosis (OR, 0.14; 95% CI, 0.06-0.30)
	Control: 242
				The -765C allele may be protective against the development of the disease in Korean women
Wang et al. 2011[29]	Case: 300	FSH receptor gene	Taiwanese	The mutant alleles of FSH receptor gene at the position 680 of amino acid (Asn680Ser) (GG genotype, 680Ser/Ser and GA genotype, 680Ser/Asn) may have a protective effect on the development of endometriosis in Taiwanese Chinese women
	Control: 337
Kang et al., 2010[30]	Case: 421	FGF2 gene	North Chinese	FGF2 754C/G polymorphism may be associated with a risk of developing endometriosis. The G allele in the FGF2 gene may potentially protect against the disease.
	Control: 421
Lee et al., 2008[31]	Case: 246	TNF-α a gene	Korean	This difference at the TNF: g.[-1031T >C] tends to increase in Stage IV endometriosis (P=0.01). The genotype frequencies at the TNF: g.[-1031T>C] and the TNF: g.[-863C >A] sites may be associated with advanced stage endometriosis
	Control: 248
Kang et al., 2008[32]	Case: 298	TIMP-2 gene	North Chinese	The frequency of the TIMP-2 -−418C/C homozygote was significantly low in patients with endometriosis (0.7%), the C/C genotype may significantly decrease the risk of endometriosis development, with an odds ratioOR of 0.18 (95% CIconfidence interval, 0.04-0.79). TIMP-2-418C/C homozygote may be a protective factor against the development of endometriosis
	Control: 324	MMP-2 gene
				No significant difference in genotype and allelotype distributions of the MMP-2−1306C→T was found between patients and control
Shan et al., 2007[33]	Case: 152	E-cadherin gene	North Chinese	There was a significant difference in the frequency of the E-cadherin 3’- UTR C --> T genotypes between endometriosis and controls (P=0.01)
	Control: 189
				When compared with the T/T+T/C genotypes, the C/C genotype had a significantly increased susceptibility to endometriosis, with an adjusted odds ratioOR of 1.79 (95% confidence intervalCI=1.17-2.76)
				E-cadherin 3’- UTR C --> T polymorphism, the -160 A/-347 GA haplotype of two promoter polymorphisms suggesting a potential role in endometriosis development
Kitawaki et al., 2006[34]	Case: 202	IL-6 gene	Japanese	The IL-6-634C/G and ICAM-1 469K/E polymorphisms synergistically affect the susceptibility for endometriosis. The frequency of ICAM-1 EE homozygotes who concomitantly carried the IL-6-634G allele was significantly higher in patients with endometriosis (P=0.0396, d.f. 2)
	Control: 236	ICAM-1 gene
				No differences in the IL-6-634C/G genotypes and allele frequencies or the ICAM-1 469K/E polymorphisms between patients and control
Tsuchiya et al., 2005[35]	Case: 79	HSD17B1 gene CYP19 gene	Japanese	Individuals having at least one A-allele (A/G or A/A genotype) of HSD17B1 showed a significantly increased risk of endometriosis (A/G genotype: adjusted OR, 3.06; 95%CI 1.21-0.74; A/A genotype: adjusted OR, 3.02; 95%CI 1.08-8.43)
	Control: 59
				There was a significant trend associating A/G + A/A genotypes with severity of endometriosis (P for trend <0.01)
				No statistically significant association was found for the CYP19 polymorphism
Kitawaki et al., 2004[13]	Case: 185	IFNG gene	Japanese	The IFNG CA-repeat polymorphism is associated with susceptibility to endometriosis
	Control: 176	IL4 gene		No differences in IL-4-590C/T genotypes and allele frequencies between control women and patients with endometriosis

SNP: Single -nucleotide polymorphism, TNF-: Tumor necrosis factor- alpha, GST: Glutathione-S-transferases, CI: Confidence interval, OR: Odds ratio