Soy compound may help fight breast cancer: study

A compound found in soy food products may help suppress the development of breast cancer, paving the way for new therapies to prevent the disease, claims a study.

Researchers at the University of Arizona in the US suggest genistein - a component of soy the foods - can protect BRCA1, a gene that plays a pivotal role in thwarting tumour development in breast tissue.

BRCA1 is a tumour-suppressor gene. When working normally, it helps keep DNA stable, protecting against genetic diseases like cancer; when BRCA1 is performing abnormally, the body's defences against breast cancer are impaired, researchers said.

A small percentage of breast cancers are caused by mutations in BRCA1, many other breast cancer patients have normal copies, but the genes have been "methylated" - wrapped in strands of carbon-based molecules that render them unreadable. The BRCA1 gene "silenced" in this manner is unable to do its job as a tumour suppressor, they said.

One receptor, the aromatic hydrocarbon receptor (AhR), silences BRCA1, triggering a cascade of undesirable effects.

When BRCA1 is unable to carry out its duties as a tumour suppressor, cancerous cells can proliferate, researchers said.

The study, published in the journal Current Developments in Nutrition, found that AhR can be targeted by genistein.

The team hopes this discovery will lead to a genistein- based therapy that can block the harmful actions of AhR.

One weapon that may be used to target AhR is found in soy, a protein-packed legume that is a major source of compounds called isoflavones, they said.

"Lifetime intake of soy in Asian women has been linked to reduced risk of breast cancer. Genistein is the predominant isoflavone found in soy and it may actually block DNA methylation" - the silencing of the BRCA1 gene," said Donato F Romagnolo, professor at University of Arizona.