Prognostic significance of estrogen and progesterone receptor expression in LNG-IUS (Mirena) treatment of endometrial hyperplasia: an immunohistochemical study.

We performed immunohistochemical analysis of estrogen (ERalpha) and progesterone receptors (PRA and PRB), phosphatase and tensin homolog (PTEN) and aromatase in endometrial hyperplasia treated with Mirena (levonorgestrel-releasing intrauterine system; LNG-IUS) and explored their prognostic significance. The baseline pre-treatment endometrial hyperplasia of a selected prospective cohort was analyzed [complex (n = 29) and atypical (n = 5)]. Study participants were categorized into those that showed endometrial regression (responders, n = 28) and those that showed non-regression or histological progression to atypia or malignancy (non-responders, n = 6). Immunohistochemical expression was expressed as a histological score (HS). Responders compared to non-responders showed significantly higher HSs for estrogen and progesterone receptors. Absence of estrogen and progesterone receptors predicted non-responder status with likelihood ratios of 9.33 (95% CI 2.19-39.81) and 2.92 (95% CI 1.47-5.79), respectively. Neither PTEN nor aromatase expression were associated with LNG-IUS therapy responsiveness. Responsiveness of endometrial hyperplasia to LNG-IUS therapy may be determined through analysis of baseline estrogen and progesterone receptors, but these exploratory findings require confirmation in a larger dataset.