Soy and Cancer

     In spite of the fact that numerous studies have shown that those with high soy consumption appear to have lower incidence of cancer than those with a low intake the web is filled with suggestions that consumption of soy causes cancer.
     A recent study has identified a powerful new anti-cancer substance in soy called lunasin, a protein in the soybean. Lunasin selectively kills cells being transformed or newly transformed into cancer cell. Lunasin appears to prevent the development of cancer cells, but does not affect established cancer cells.
     Lunasin has an epigenetic effect upon cells. It alters the way the DNA expresses itself. Research on lunasin explains why soy appears to prevent cancer, but is not very effective in treating cancer once it develops.

Reference:
de Lumen, Ben o., Lunasin: A cancer-preventative soy peptide, Nutrition Reviews, January 2005, 63(1):16-21.