Protection against breast cancer with genistein: a component of soy

Abstract

Breast cancer is the most common cancer in women. Because genetics is believed to account for only 10-15% of breast cancer cases, the environment, including nutrition, is thought to play a significant role in predisposing women to this cancer. Studies of Asian women suggest that those who consume a traditional diet high in soy products have a low incidence of breast cancer, but that among emigrants to the United States, the second generation, but not the first, loses this protection. These findings suggest a possible common mechanism of action for breast cancer protection from early, specific nutritional exposure. Genistein, an isoflavone found in soy, has been reported to have weak estrogenic and antiestrogenic properties, to be an antioxidant, to inhibit topoisomerase II and angiogenesis, and to induce cell differentiation. In studies of the mammary glands of immature rats, we showed that genistein up-regulates the expression of the epidermal growth factor receptor shortly after treatment, which may be responsible for the increased cell proliferation seen at that age. We hypothesize that the early genistein action promotes cell differentiation that results in a less active epidermal growth factor signaling pathway in adulthood that, in turn, suppresses the development of mammary cancer. We speculate that breast cancer protection in Asian women consuming a traditional soy-containing diet is derived from early exposure to soybean products containing genistein. We believe that early events are essential for the benefits of cancer protection.

DNA topoisomerase II, genotoxicity, and cancer

“…They are an integral component of the human diet and are believed to provide a number of health benefits to adults, including chemoprevention leaves [105][106][107][108][109][110][111][112]. Bioflavonoids have a variety of effects on human cells.…”

“…Bioflavonoids have a variety of effects on human cells. They represent the most abundant natural source of antioxidants, potently inhibit tyrosine kinases, and exhibit anti-proliferative and pro-apoptotic affects leaves [105][106][107][108][109][112][113][114][115][116]. However, they also display cytotoxic and genotoxic properties and many are potent topoisomerase II poisons [117][118][119][120].…”

Protective Effect of Soybean against Hepatocarcinogenesis Induced by DL-Ethionine

“…The protective effect of soybean might also be due to its content of isoflavones, like genistein, which are believed to have a potential role in reducing tumor incidence (Hacker et al, 1998). These isoflavones have been reported to reduce the risk of breast cancer (Messina, 1999;Lamartiniere, 2000) and urinary tract cancer (Su et al, 2000) in animal studies. Lee et al (1995) reported that soybean isoflavones may have an anticarcinogenic effect by suppressing the early stages of hepatocarcinogenesis induced by diethylnitrosamine.…”

“…During the past two decades, attention has been focused on the possible role of soybeans, which contain trypsin inhibitors, isoflavones, and phytic acid (Anderson and Wolf, 1995), on reducing or delaying the incidence of many tumors in experimental animals (Roll et al, 1980;Corasanti et al, 1982;Barnes et al, 1990;Messina and Messina, 1991;Webb et al, 1992;Anderson and Wolf, 1995;Thiagarajan et al, 1998;Appelt and Reicks, 1999;Messina, 1999;Onozawa et al, 1999;Lamartiniere, 2000;Su et al, 2000;Zaizen et al, 2000).…”

Efeitos das isoflavonas sobre o assoalho pélvico e a vascularização peri-uretral de mulheres na pós-menopausa

“…Várias alternativas à terapia estroprogestativa estão sendo avaliadas, entre elas as isoflavonas, que apresentam afinidade pelos receptores de estrogênio, que seriam responsá-veis pelos seus efeitos agonistas 9 . O interesse no estudo das isoflavonas como alternativa terapêutica advém de vários estudos publicados realçando os efeitos das isoflavonas nos sintomas menopáusicos 9,10 , vagina e endométrio 10,11 e na mama 10 .…”