Estrogen and progesterone receptor expression in patients with uterine smooth muscle tumors

OBJECTIVE: To investigate the expression of estrogen and progesterone receptor in uterine leiomyomas, smooth muscle tumors of uncertain malignant potential (STUMP), and leiomyosarcomas (LMS), and to assess the correlation between steroid receptor expression and clinicopathologic parameters in LMS. DESIGN: Estrogen/progesterone receptor expression was investigated by immunohistochemistry. SETTING: Department of Gynecology and Obstetrics of the University Hospital of Vienna. PATIENT(S): Twenty-six women with leiomyoma, 24 with STUMP, and 21 with LMS of the uterus. INTERVENTION(S): Formalin-fixed, paraffin-embedded tissues were sectioned and stained. MAIN OUTCOME MEASURE(S): Number of tumor cells stained. RESULT(S): Significant differences regarding the frequency of estrogen receptor expression were observed between LMS and leiomyoma and STUMP and leiomyoma (P<.05). The progesterone receptor expression did significantly differ between LMS and STUMP (P=.05), and LMS and leiomyoma (P<.05). In uterine LMS, the relationship between estrogen/progesterone receptor expression and clinicopathologic parameters did not reach statistical significance (P>.05), and neither of the markers studied revealed prognostic significance (P>.05). CONCLUSION(S): The present study observed significant differences of steroid receptor expression between uterine leiomyoma, STUMP, and LMS. Our data indicate that the progesterone receptor may be an especially useful marker to distinguish cases of malignant smooth muscle tumors in which histological features are ambiguous or borderline.