Epidemiological studies in soy consumers regularly demonstrate a reduced incidence of various types of cancer. This observation of cancer-preventive effects is backed by experimentally discovered mechanisms of action of genistein and analogous compounds potentially contributing to the clinical effect – mechanisms which have already led to the development of new drugs based on analogues of genistein. Phenoxodiol, an in comparison with genistein minimally changed synthetic isoflavone, is currently in an advanced stage of clinical testing as an anti-cancer drug.

The results from research clearly show that genistein does not only have a cancer-inhibiting potential, but that soy and isoflavones also support the effect of anti-cancer agents such as cisplatin and tamoxifen.
Targets for anti-tumour strategies confirmed with isoflavones in vitro, in vivo and partly also in clinical trials are

• Activation of the estrogen receptor beta (ER-β) as a counter-measure against proliferation-enhancing effects of estrogens at the alpha-receptor (ER-α);
• Prevention of neoangiogenesis (formation of new blood vessels for the supply of cancer tissue with nutrients and oxygen) with the aim of reducing the speed of cancer growth;
• Inhibition of the Vascular Endothelial Growth Factor (VEGF) with the aim of preventing the assembly of new microcapillaries in the process of neoangiogenesis;
• Inhibition of tyrosine kinase as a possible approach to the inhibition of neoangiogenesis;
• Inhibition of matrix-metalloproteases (MMPs) as an approach to the prevention of the emigration of metastases from the tumour; and
• Re-establishing a normal rate of apoptosis (programmed cell death).