Steroid synthesis in intratumoral stromal and carcinoma cells and the potential sites at which flavones and isoflavones may inhibit the production of biologically active oestrogens. Androgens taken up by carcinoma cells include androstenedione and DHEA, the latter of which is converted to androstenedione by 3β-HSD1. Androstenedione is converted to oestrone by aromatase. Oestrone sulphate is converted to oestradiol by ETS and 17β-HSD.ETS, oestrogen sulfatase; EST, oestrogen sulfotransferase/SULT1E1; HSD, hydroxysteroid dehydrogenase.

Basically, it's stating flavones are anti-aromatase, while red clover is the on switch between 17 beta HSD and ER-a (estrogen receptor alpha, the growth receptor).