Oestrogen metabolism in cultured human breast tumours.

The interconversion of tritium labelled oestrone and oestradiol-17β has been investigated in human breast tumours maintained in organ culture for 3 days. Benign tumours were significantly different from scirrhous carcinomata both in the concentration of radioactivity taken up by the tissue and in the ratios of oestradiol-17β/oestrone achieved. The fact that malignant tumours were able to convert oestrone to oestradiol-17β is of interest in view of the relatively high plasma levels of oestrone in post-menopausal women.