Cancer development consists of three separate stages: tumor initiation, tumor promotion and tumor progression. Polyphenols, including Resveratrol, have been found to impact all three.

Initiation occurs when free radicals attack the cell membrane, the mitochondria and the DNA of the cell's nucleus. The body uses antioxidants to combat the free radicals.

Promotion is a lengthy, yet still reversible process whereby precancerous cells accumulate and grow. This phase is greatly enhanced by inflammation, not only at the site of the cancer, but throughout the body.

Progression is the final and most deadly stage of cancer, whereby the cancer creates thousands of new blood vessels to supply its own growth, and can seed new cancer growths elsewhere in the body.

Dr. John Pezzuto of Purdue University screened tens of thousands of naturally occurring compounds, and in 1997 he and his team published a paper in the journal Science entitled "Cancer Chemopreventive Activity of Resveratrol, a Natural Product Derived from Grapes." Reseachers demonstrated that phytoalexins (aka polyphenols including Resveratrol, Quercetin and others) could inhibit all three stages of cancer development. First, it can neutralize free radicals as a powerful anti-oxidant in the initiation stage. Second, it acts as an anti-inflammatory during the promotion stage. Third, it inhibits the formation of new blood vessels supplying the tumor in the progression stage.

This paper served to initiate an enormous response from other scientists. Literally hundreds of laboratories have studied, and produced thousands of papers to date on the biology and science behind such cancer prevention caused by Resveratrol and other plant polyphenols. Polyphenols including Resveratrol, Quercetin and others naturally found in red-wine grapes are now being evaluated for the treatment and prevention of many cancers.

Cancers Inhibited by Resveratrol in Animals and Human Cell Models (Source: The Longevity Factor, p112)

Breast Esophagus Lung Metastasis to bone Ovary Squamous cell

Cervical Leukemia Lymphoma Neuroblastoma Pancreas Stomach

Colon Liver Melanoma Oral cavity Prostate Thyroid

For example, Resveratrol has been showed to delay the occurrence of breast cancer in laboratory mice. Several polyphenols found in red-wine grapes including catechin, epicatechin, Quercetin, and Resveratrol have shown some effectiveness against prostate cancer. Lung cancer tumor growth was shown to be inhibited, and the formation of blood vessels retarded in animal studies using Resveratrol and Quercetin. And there is now evidence that polyphenols may be a natural sunblock, useful in the treatment and prevention of skin cancers. The list goes on to include effectiveness in many cancers including: colon, lung, ovary, kidney, liver, pancreas, thyroid, and blood (leukemia).

According to Dr. Joe Maroon, in his book The Longevity Factor, "Now we see why the discovery of xenohormesis may be one of the most significant breakthroughs in the prevention of cancer. Xenohormetic molecules from stressed plants -- in particular stressed red grape skins -- activate our sirtuin enzymes ... Much needs to be learned about the molecular mechanisms by which sirtuin activation is cancer protective, but the hundreds of studies done independently on the sirtuin genes and enzymes and now on xeno factors [polyphenols] are converging."

So as not to overstate the effectiveness in treating cancers, it should be said that research is ongoing. Studies to date have been performed on animals and laboratory-grown human cancer cell cultures. These types of studies are required precursors to full-scale human clinical trials which have as of now been initiated on various forms of cancer. Still, despite the lack of definitive cancer protective traits of polyphenols in human trials, the potential for cancer prevention is indeed promising.

References

Grape extract can inhibit breast cancer. A 2002 study by Dr. Keith Singletary at the University of Illinois indicates that components in grape juice can inhibit the growth of certain types of breast cancer cells in rats. At the end of the study, mammary tumor mass was reduced by 28% to 36% and the number of tumors per animal was reduced by 45% to 65%. More...

Resveratrol prevented tumor growth. At Ahime University in Japan, moderate doses (2.5 and 10 mg/kg) of Resveratrol significantly prevented the growth of tumors and reduced the size (by 46%) and metstasis (by 56%) of lung cancer tumors by in mice. More...

Dietary antioxidant flavonoids protect against post-menopausal breast cancer. Research study at Columbia University showed a 25-50% reduction in risk of tumor formation. More...

Resveratrol shows cancer chemopreventive activity. A 1997 study at the University of Illinois showed Resveratrol to have cancer chemopreventive activity in assays representing three major stages of carcinogenesis. Resveratrol was found to act as an antioxidant and antimutagen and to induce phase II drug-metabolizing enzymes (anti-initiation activity); it mediated anti-inflammatory effects and inhibited cyclooxygenase and hydroperoxidase functions (antipromotion activity); and it induced human promyelocytic leukemia cell differentiation (antiprogression activity). More...

Resveratrol induced marked growth inhibition in five human cancer cell lines. In a 2002 epidemiological study at Columbia University, Resveratrol induced growth inhibition, S-phase arrest, apoptosis, and changes in biomarker expression. More...

Resveratrol inhibits cancer growth. This 2004 UCLA review published in "Anti-Cancer Research" concluded that: "Besides cardioprotective effects, Resveratrol exhibits anticancer properties, as suggested by its ability to suppress proliferation of a wide variety of tumor cells, including lymphoid and myeloid cancers; multiple myeloma; cancers of the breast,
prostate, stomach, colon, pancreas, and thyroid; melanoma; head and neck squamous cell carcinoma; ovarian carcinoma; and cervical carcinoma. More...

Resveratrol inhibits growth of human colon cancer cells by 70%. A 2000 study by the Digestive Oncology Laboratory in Strasbourg, France, investigated the anticancer properties of Resveratrol. More...

Enzyme produced by tumors converts Resveratrol into anticancer agent piceatannol. This study, published in the British Journal of Cancer explored the mechanisms by which Resveratrol might become a powerful antileukemic agent. More...

Reduction and inhibition of intestinal tumors. A study at South Dakota State University found that Resveratrol and grape extract significantly decreased the incidence and multiplicity of tumors in the small intestine in rats. More...