Validation of Epigenetic Markers in Endometriosis

Endometriosis is a gynecological disease that affects 1 in 10 women during their reproductive years, cause incapacitating pelvic pain and infertility. Endometriosis is characterized by the growth of endometrial tissue outside the uterine cavity. Endometriosis has no cure, its diagnosis can only be done via surgery, there are no non‐invasive markers and its etiology is unknown. Epigenetic mechanisms may play an important role in the etiology of this disease. The modification of histones by acetylation and methylation of lysine residues has been shown to regulate gene expression by changing chromatin structure. We have shown by ELISA that endometriotic lesions have high levels of acetylated histone 3 at lysine residue 9 (H3K9ac). Aim To measure H3K9ac levels using immunohistochemistry (IHC). Methods Using a Tissue Microarray (TMA) composed of 163 biopses (endometriotic lesions and control tissues) we will assess levels of H3K9ac by IHC. Troubleshooting experiments identified the 1:100 as the appropriate dilution of the antibody. Results We expect that endometriotic lesions will express lower levels of H3K9ac than controls. Also, we expect that endometrium of patients express higher levels of H3K9ac than endometrioctic lesions. IHC will be able to show the cell specificity (i.e., glands vs. stroma) and will confirm the nuclear localization of this histone mark. In addition, we will be able to determine possible differences in this mark by lesion type (ovarian vs. peritoneal). These results will help understand how genes are regulated in endometriosis, and may support the use of novel treatments for this incurable disease. R25GM096955