The relative ability of the antiestrogen, tamoxifen, and its monohydroxy and desmethyl metabolites to displace tritiated estradiol from estrogen receptors isolated from human breast carcinoma was determined. 4-Hydroxytamoxifen binds to the estrogen receptor with affinity equal to estradiol, and with 25-50 times higher affinity than does tamoxifen. Desmethyltamoxifen binds to the estrogen receptor with less than 1 per cent of the affinity of tamoxifen. Blood level determination of tamoxifen species in breast cancer patients receiving the drug indicated that after 3 weeks of therapy, desmethyltamoxifen levels were 1.2-1.8 times greater than tamoxifen levels and 4-hydroxytamoxifen levels were 2-18 per cent of parent drug concentrations. Thus, because of its high affinity for the estrogen receptor, the 4-hydroxy metabolite may play a significant antiestrogenic role following tamoxifen therapy, despite its low relative abundance. Desmethyltamoxifen, on the other hand, may have only minor importance as an anti-estrogenic agent following tamoxifen treatment, due to its poor affinity for the estrogen receptor coupled with blood levels that are at most 75 per cent greater than tamoxifen levels at steady state.

LAIP alterations in refractory/relapsed AMLs are common findings. Presence of persistent disease indicates a poor prognosis, regardless of cytogenetic risk or expression of CD7 or CD56. Discordance between cytogenetic and LAIP changes suggests that gross cytogenetic clonal evolution during disease progression only partly contributes to immunophenotypic instability.

Steroid receptor assays play an important role in determining the efficiency of endocrine therapy for patients with breast cancer. Other tumors could also be hormonally dependent and patients with these tumors might also benefit from endocrine manipulation. Thus, patients with meningiomas were tested for the presence or absence of estrogen and progesterone receptors. The results showed that a majority of meningiomas lacked estrogen receptors but contained large amounts of progesterone receptor. Therefore , it should be possible to use antiprogestin therapy in cases where complete surgical resection of meningiomas is not possible. Cancer 49:633-636, 1982. RECENT REPORT has shown that intracranial me-A ningiomas contain estrogen receptors.2 These tumors were investigated for the presence of estrogen receptors (ER) because a majority of meningiomas are found in women and are clinically aggressive during pregnan~y.~.'' To evaluate these observations we assayed six tumors from patients with meningiomas for ER. In addition, we assayed the tumors for the presence of progesterone receptor (PR). In contrast to the work of Donne11 et a1.,2 we found no significant quantities of ER in specimens assayed. However, we did find significant quantities of PR in four of the six meningiomas. The amounts of PR were as high as levels of PR found in breast carcinoma. These results suggest that these tumors might be hormone dependent and that the patients might be managed by various forms of endocrine therapy. Case Reports Case I This 61-year-old white woman had a six-month history of a gradually increasing roaring noise in her right ear. Physical exam showed no abnormality except for a slight hearing deficit in the right ear. A CT scan demonstrated a 6-cm mass on the right side, starting over the convexity and extending to the falx. At surgery, a right occipitoparietal tumor was found that invaded and occluded the superior sagittal sinus. As much