Although androgen resistance has been characterized in men with a normal chromosome complement and mutations in the androgen-receptor gene, a mutation in the gene encoding estrogen receptor α (ESR1) was previously described only in one man and not, to our knowledge, in a woman. We now describe an 18-year-old woman without breast development and with markedly elevated serum levels of estrogens and bilateral multicystic ovaries. She was found to have a homozygous loss-offunction ESR1 mutation in a completely conserved residue that interferes with estrogen signaling. Her clinical presentation was similar to that in the mouse orthologue knockout. This case shows that disruption of ESR1 causes profound estrogen resistance in women. (Funded by the National Institutes of Health.)

Monoclonal antibody (MAb) OC125 binds to approximately 80% of epithelial ovarian cancers. Serum antigen, CA125, can be detected in these patients. 131I-OC125-F(ab')2 was injected into 5 ovarian carcinoma patients with preinjection serum levels of 150 to 9,000 CA125 U/ml. Patients received the antibody intravenously in doses ranging from 0.46 to 0.94 mg with a specific activity of approximately 2.5 mCi/mg 131I. The half-life in the circulation was approximately 30 hr and was independent of serum CA125 levels. Clearance of 131I from the circulation fitted an open, one-compartment mathematical model. Gel filtration chromatography revealed antibody-antigen complexes in sera 15 min after injection of the radiolabelled antibody. By 5 days after injection, the free form of OC125 antibody could not be detected in the serum. The rate of complex formation correlated well with the observed preinjection serum CA125 levels. This direct correlation was verified in vitro using purified CA125 antigen and radiolabelled OC125 F(ab')2 fragments. The specific effects of complex formation on tumor localization remains unclear. However, the presence of complexes should not be ignored, when planning for diagnostic imaging or immunotherapy with OC125 or other MAbs reacting with circulating antigen.