Problem The aim of this study was to investigate the relationship between the polymorphisms of the tumor necrosis factor-α (TNF-α) and TNF receptor (TNFR) genes and serum levels of TNF-α and its soluble receptor (sTNFR) in Korean women with endometriosis.
Method of study The TNF-α C(−857)T, C(−863)A and T(−1031)C, and TNFR1 A(36)G, TNFR2 T(676)G, A(1663)G, T(1668)G and C(1690)T polymorphisms, and serum levels of TNF-α, sTNFR1, and sTNFR2 were analyzed in women with (n = 105) and without endometriosis (n = 101).
Results Serum sTNFR1 and sTNFR2 levels were significantly higher in women with endometriosis than in those without endometriosis, whereas no difference in serum TNF-α level was noted. Single polymorphisms of TNF-α and TNFR genes were not significantly different between the two groups. The frequencies of the TNF-α T/C/C haplotype allele and the TNFR2 G/G/T haplotype allele were significantly decreased in women with endometriosis compared to women without endometriosis. Women carrying at least one copy of the TNFR2 T/G/T and /or G/G/C haplotype allele had an approximately two times higher risk of endometriosis than women without these haplotype alleles.
Conclusion The haplotype alleles of the TNF-α and TNFR2 gene polymorphisms are genetic factors associated with endometriosis, and circulating sTNFR rather than TNF-α, may be involved in the development of endometriosis in Korean women.