Lack of nuclear estrogen binding in benign mesothelioma of the uterus

Estrogen binding sites in a benign mesothelioma of the uterus was studied by in vitro steroid autoradiography. Unlike normal myometrium, which shows distinct supanuclear localizations of tritiated estradiol, the cellular components of the benign mesothelioma do not appear to have estrogen receptors. Serial sections through the tumor failed to localize sites of estrogen binding. These findings are congruent with an undifferentiated mesothelial organ for the tumor and suggest a lack of response to endogenous sex steroids.