Aim: Endometriosis is an estrogen-dependent disease that causes pelvic pain and infertility. In this study, to examine the estrogen-dependent mechanisms of human endometriosis, we focused on the expression patterns of the steroid receptor coactivator (SRC) family of cofactors for nuclear steroid receptors and estrogen receptor α (ERα).

Material and methods: The expression patterns of SRC-1, transitional intermediary factor 2 (TIF2), SRC-3, and ERα, were analyzed by immunohistochemistry of normal endometrium and ovarian endometriotic tissue. In addition, reverse transcription polymerase chain reaction (RT-PCR) for the SRCs was performed for ovarian endometriosis.

Results: SRCs were expressed in all examined tissues. The expression levels of SRC-1 and the number of SRC-1-positive cells in ovarian endometriosis were greater than those of TIF2 and SRC-3. In addition, immunohistochemistry showed that ERα was colocalized with SRC-1 in almost all glandular and many stromal cells in ovarian endometriotic tissue.

Conclusion: The present study demonstrates the expression pattern of SRCs in ovarian endometriosis. It appears that SRC-1 is predominant among the other SRC family members and colocalizes with ERα. Although further study is needed, SRC-1 may affect the transcriptional activity of ERα in human ovarian endometriosis.