Aromatase activity in uterine leiomyomata.

Of the 24 samples of leiomyoma tissues examined 14 were shown to have aromatase activity in vitro. In contrast only 1 of 12 samples of myometrium had any demonstrable activity. Measurements of tissue oestrogen levels showed no correlation with the amount of aromatase activity although oestradiol levels were consistently higher in the tumour tissues compared with the normal myometrium.