Increased expression of human chorionic gonadotropin/human luteinizing hormone receptors in adenomyosis

Adenomyosis is a benign disease in women in which myometrium is invaded by endometrial glands and stroma. Our laboratory recently demonstrated that normal human endometrial glands and stroma express the hCG/LH receptor gene. This prompted us to investigate whether invading glands and stroma in adenomyosis also express this receptor gene. Fifteen hysterectomy specimens with confirmed histological diagnosis of adenomyosis were examined for hCG/LH receptors by in situ hybridization and immunocytochemistry. The results showed that invading glands contained more receptor mRNA and receptor protein than noninvading glands in the same endometrium. However, the degree of difference between invading and noninvading glands varied among the patients. The higher receptor expression in invading glands is specific because the invading and noninvading stroma showed similar receptor expression, invading and noninvading glands showed similar expression of cadherin, a cell adhesion receptor, and ectopic and eutopic endometrial glands from endometriosis showed similar hCG/LH receptor expression. In summary, the present results demonstrate that invading endometrial glands in adenomyosis selectively express more hCG/LH receptor mRNA and immunoreactive receptor protein than noninvading glands. Whether this increased receptor expression is the cause or a consequence of myometrial invasion of glands in unknown.