Dr. Paul Sylvester and colleagues at the Pullman campus compared the effects of tocotrienol on inhibition of cancer cell growth with those of tocopherol, the commonly available formulation of vitamin E.Dr. Sylvester reported the findings at an invited symposium on cancer prevention and control held recently at the National Institutes of Health.

The researchers cultured normal mouse mammary epithelial cells and a mammary adenocarcinoma cell line in media containing either of the two vitamin E compounds.Tocopherol had no effect on cell proliferation after 5 days or cell death at 24 hours.In contrast, tocotrienol inhibited cancer cell proliferation and induced cell death at low concentrations.

"Cancer cells are especially sensitive to tocotrienol," Dr. Sylvester told Reuters Health.In the study, normal mammary epithelial cells required relatively high concentrations of tocotrienol to induce cell death and inhibit cell proliferation.Malignant cells reacted at much lower concentrations.Dr. Sylvester said that it appeared that the cancer cells absorbed tocotrienol more rapidly than normal cells.

After 2 years of in vivo and in vitro studies, Dr. Sylvester reported that he has seen no evidence of toxicity with tocotrienol.The researchers believe that the antiproliferative and cytotoxic qualities of tocotrienol may eventually translate to clinical benefits in the prevention and treatment of breast cancer.

Dr. Sylvester notes in a Washington State University press release that the palm oil sold in the US is refined, a process which removes its protective qualities, he said.Dr. Sylvester obtains his supply from the Palm Oil Research Institute in Malaysia.

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