Abstract: Endometriosis（ＥＭｓ）, an estrogen-dependent inflammatory disease, is still unclear in pathogenesis. More and more evidence proved that epigenetic characteristics of several genes were associated with EMs. Epigenetics is referred to the heritable genetic changes such as DNA methylation, histone covalent modification and chromatin conformation changes, which do not change DNA sequence. Epigenetic abnormality may trigger a series of pathological disorders including tumors. Hypomethylation of CpG islands in aromatase gene and（ｏｒ） trans-acting factor genes up-regulated the expression of aromatase mRNA in the ectopic tissues. Low expression of ERα and significantly high expression of ERβ were found in the ovarian ectopic epithelial and stromal cells, while high expressions of both PRα and PRβ in the eutopic cells. The promoter of steroidgenic factor-1（ＳＦ－１） was hypomethylation in ectopic cells, while it was hypermethylation in eutopic cells. In addition, the decreased expressions of both E-cadherin gene in ectopic tissues and homeobox A10 gene in eutopic tissues were also related to EMs. Environmental factors may be involved in EMs by epigenetic mechanism. This review summarized the roles of epigenetics and environmental factors in the pathogenesis of EMs.

Key words: Endometriosis, Genetics, CpG islands, Methylation, Aromatase