Aberrant methylation at HOXA10 may be responsible for its aberrant expression in the endometrium of patients with endometriosis

HOXA10, expressed in endometrium, plays an important role in uterine receptivity at the time of implantation. In the endometrium of women with endometriosis, its expression is reduced. The aim of this study was to determine whether the observed aberrant expression of HOXA10 is caused by aberrant methylation of the gene. Endometrial tissues were collected from 6 women with laparoscopically confirmed endometriosis, and 4 women who underwent tubal ligation and were confirmed to have no endometriosis. In addition, menstrual blood from 5 women with no gynecologic complaints was collected and also used as controls. Methylation-specific polymerase chain reaction (PCR) and bisulfite sequencing were performed in 3 fragments in 2 regions of HOXA10 to detect difference in methylation patterns. Real-time reverse transcriptase (RT)-PCR was also performed to measure expression levels of HOXA10 in select cases and controls. In all 3 fragments, there were highly statistically significant differences in methylation patterns between women with endometriosis and those without endometriosis. The expression level of HOXA10 was lower in women with endometriosis than those without, as previously reported. There is aberrant methylation in the endometrium of women with endometriosis compared with those without endometriosis. The aberrant methylation at HOXA10 may be responsible for the aberrant gene expression in the endometrium of women with endometriosis. This finding suggests that endometriosis may also be an epigenetic disease.