II.6 Alterations in steroid hormone receptors in the tamoxifen-treated endometrium

Abstract

Abstract Although the mechanism of tamoxifen-induced endometrial neoplasia is thought to be via an oestrogenic effect of tamoxifen, there are few data confirming this. Since sex steroid hormones regulate endometrial growth via interaction with their receptors, oestrogen receptor (ER) and progesterone receptor (PR), a clinicopathological evaluation was performed to determine if these seemingly oestrogenic-like actions of tamoxifen on the uterus are associated with alterations in the expression of endometrial steroid receptors. To evaluate whether tamoxifen has oestrogenic endometrial effects as defined by histology or alterations in steroid receptor expression, 19 postmenopausal (PMP) tamoxifen-treated breast cancer patients who also had endometrial sampling were identified. To examine the subgroup of 15 polyps, age-matched, non-hormonally treated patients with polyps (n = 8) or atrophic endometria (n = 5) served as comparison groups. Proliferative (n = 3) and secretory (n = 5) endometria were procedural controls. Immunohistochemistry (IH) for steroid receptor ER and PR was performed.