A comparative study of the estrogen receptor ratio in myometrium and uterine leiomyomas

Estrogen receptor (ER) content in myoma and myometrium was determined by radio-receptor assay (RRA), and ER staining was performed by immunocytochemical staining, i.e. the peroxidase-antiperoxidase (PAP) method, in uterine samples from eight patients with uterine leiomyoma. ER content in myoma tended to be hither than that in myometrium, but the difference was not significant. The distribution pattern of ER staining was thought to be an important criterion. When the data were compared on the basis of the number of cells in the site where the largest number of positive cells aggregated, the number for myoma was significantly higher than that for myometrium (P less than 0.05). These results suggest that myoma contains more ER positive cells to obtain estrogen effects than myometrium.