The increased frequency of meningiomas in women compared with men, and the rapidly progressive course of these tumors in pregnant patients suggest that hormones may be involved in this disease. Tumor tissue from six patients with meningiomas was analyzed for estrogen-receptor protein. Two patients had tumors with very high concentrations of this protein, approaching that found in hormonally sensitive breast carcinoma. The biochemical and possible clinical significance of these findings is discussed.; Because the epidemiology and clinical course of some meningiomas suggest that these tumors may be hormonally sensitive and that they may contain estrogen receptor protein, and because two-thirds of all intracranial meningiomas and 80% of all spinal meningiomas occur in women, the relationship between pregnancy (and its hormonal alterations) and development of these meningiomas was studied using tissue samples obtained from 6 patients with meningiomas. These samples were analyzed for estrogen receptor protein and were then correlated with preoperative and intraoperative observations. The 6 cases studies are presented, and the following results were apparent. Significant quantities of estrogen receptor protein were found in tissue from 4/6 patients (212 [ this patient was 10 weeks pregnant] , 62, 57, and 223 total receptors in fmol/gm.). Tumor tissue from 3/4 women and 1/2 men contained measurable estrogen receptor protein. The highest concentrations were found in 2 mid-30-year-old premenopausal women (1 of whom was 10 weeks pregnant). Common findings in these cases were premenopausal status, prominent tumor vascularity, and adjacent tissue invasion. The remaining female whose tissue sample showed estrogen receptor protein was classified as a perimenopausal woman based on a 6-month period of amenorrhea within the previous year. No significant estrogen-receptor activity was found in the cases of 1 man and 1 woman. The sedimentation coefficient of the estrogen receptor protein varied among the tissue samples. In 2 cases, the receptor protein was present in primarily the 4s fraction, whereas in the 2 other cases the concentration was greatest in the 8s sedimenting fraction.
