Immunohistochemical Expression of Estrogen Receptors in Chondrosarcomas and Enchondromas

Abstract

Immunohistochemical expression of estrogen receptors α and β was studied in chondrosarcomas and enchondromas and was correlated with chondrosarcoma grade, type, and dedifferentiation. Estrogen receptor α was studied in 37 chondrosarcomas, 10 enchondromas, and 2 extraskeletal myxoid chondrosarcomas. Estrogen receptor β was studied in 23 chondrosarcomas, 6 enchondromas, and 2 extraskeletal myxoid chondrosarcomas. Ventana prediluted monoclonal anti-ER α (clone 6F11) and Biogenex prediluted polyclonal anti-ER β were used on the Ventana ES autostainer and BenchMark XT IHC/ISH, respectively. Percent of cell staining and intensity (+, ++, or +++) was evaluated. Overall, 61% of conventional chondrosarcoma and 60% of enchondroma were positive for estrogen receptor α. Low-grade chondrosarcoma expressed estrogen receptor α more frequently than high-grade chondrosarcoma (P ≤ .001). Extraskeletal myxoid chondrosarcomas expressed estrogen receptor α; it was not expressed in dedifferentiated chondrosarcoma. Overall, 89% of conventional chondrosarcomas and 83% of enchondromas were positive for estrogen receptor β. Low-grade chondrosarcomas expressed estrogen receptor β more frequently than high-grade chondrosarcomas (P ≤ .05). Extraskeletal myxoid chondrosarcomas expressed estrogen receptor β; it was frequently lost in dedifferentiated chondrosarcoma.