Aberrant endometrial DNA methylome of homeobox A10 and catechol-O-methyltransferase in endometriosis

Purpose Differential methylation of both HOXA10 and catechol-O-methyltransferase (COMT) has been reported in different endometrium disorders, and the two genes are linked through the estrogen pathway. The current study investigates the DNA methylation of HOXA10 and COMT in ectopic and eutopic endometrial tissues and its correlation with and the occurrence of endometriosis in women from Xinjiang province in China. Methods In the current study, 120 patients with endometriosis were recruited from our hospital between January 2011 and June 2014. The DNA methylation sites of HOXA10 and COMT were detected using a DNA methylation array. The methylation levels of specific sites were compared between ectopic and eutopic endometrial tissues via pyrosequencing. Results Five differentially expressed CpGs were localized in the promoter region of the COMT gene and expressed significantly higher in the ectopic endometrium than the eutopic endometrium (P < 0.001). Two out of the five differentially expressed CpGs in the HOXA10 gene located in the promoter region were both significantly lower (nearly half) in the ectopic endometrium than the eutopic endometrium (P < 0.001). Conclusions To summarize, significant differential methylation of HOXA10 and COMT promoter regions was found between the ectopic and eutopic endometrial tissues. This is the first study investigating the methylation of HOXA10 and COMT genes and their linkage to endometriosis in Chinese patients.