The Association between TNF-alpha Gene Polymorphisms and Endometriosis in An Iranian Population

Objective Objective: TNF-α is an important cytokine in acute inflammatory response to infective factors. It seems that this response increases in patients with endometriosis due to presence of cytokines such as TNF-α which has been investigated in patients with endometriosis in different populations. This study aimed at examining four polymorphisms; TNF-α -238G/A, -308G/A, -857C/T and -863C/A associated with susceptibility to endometriosis in an Iranian population. MaterialsAndMethods Materials and Methods: We included 150 women with endometriosis and 150 women without endometriosis in this case-control study and collected 4 ml blood from all subjects. After DNA extraction, the polymorphisms were determined by PCR-RFLP analysis. Results Results: The frequency of TNF-α -863C/A allele in case and control groups showed a significant difference (OR=1.56, 95% CI=1.0-2.4, P=0.047). No significant difference in the allele frequencies of the -238G/A (OR=1.07, 95% CI=0.51-2.25, P=0.862), -308G/A (OR=1.27, 95% CI=0.69-2.34, P=0.438) and -857C/T (OR=0.97, 95% CI=0.62-1.49, P=0.887) polymorphism in the TNF-α gene was found between the case and control groups. We adjusted all four polymorphism genotypes by age and BMI, but no significant difference was found between the groups. There was a direct relationship between the case and control and BMI of the -238G/A (OR=0.92, 95% CI=0.86-0.99, P=0.022), -308G/A (OR=0.919, 95% CI=0.86-0.99, P=0.019), -857C/T (OR=0.93, 95% CI=0.86-0.99, P=0.047) and -863C/A (OR=0.92, 95% CI=0.85-0.98, P=0.016). Conclusion Conclusion: For the first time the association of the four polymorphisms in the promoter region of the TNF-α gene with endometriosis has been conducted in the Iranian women. The present research reveals the -863 A allele may play a role in incidence of endometriosis among Iranian women. Development of endometriosis among those people with -863 A allele seems low. According to the results, the current study indicates that there might be a direct relationship between BMI (Body Mass Index) and progression of endometriosis.