Estrogen receptor assay in the differential diagnosis of adenocarcinomas.

Estrogen receptor determination by the sucrose gradient method was applied to 295 tumor tissues of various origins. Estrogen receptor of the 8 S type was found only in adenocarcinoma of the breast, uterus, and ovary. Of 19 patients with metastatic carcinoma of unknown origin, four benefited from estrogen receptor study (ie, appropriate therapy could be initiated) and one was helped retrospectively on the clinical diagnosis. Estrogen receptor assays may also be useful in determining whether bilateral breast involvement represents two primary lesions or metastasis. Estrogen receptor studies should be included in evaluating cancers of unknown origin in female patients.