The research was presented at the 96th Annual Meeting of the American Association for Cancer Research (AACR) in Anaheim, Calif. BRCC36 directly interacts with the BRCA1 protein. Almost all invasive breast cancer cells have elevated BRCC36 levels compared to normal breast milk-duct cells.
"Since BRCC36 directly affects BRCA1 and BRCA1 is activated after exposure to radiation, we wanted to see if BRCC36 might be important in this response," said Xiaowei Chen, Ph.D., a Fox Chase postdoctoral researcher in the laboratory of geneticist Andrew K. Godwin, Ph.D., and the study's lead author.
Working with breast-cancer cell line MCF-7, the Fox Chase scientists reduced BRCC36 expression by 80 percent. They then exposed the cells to radiation, similar to that used in breast cancer treatment. They found that the number of breast cancer cells killed by the radiation increased by about 10 percent compared to cells that did not have their BRCC36 levels reduced.
"These findings hold promise for future breast cancer treatments," Chen said. "BRCC36 may be a target to manage radiation-resistant breast cancer cells. Our next step is to find out why the cells with reduced BRCC36 are more sensitive to radiation."
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The interest in green tea catechins and other polyphenols – antioxidants found in many plants that give some flowers, fruits and vegetables their coloring – derives from traditional Chinese medicine, and the observation of lower cancer rates among Asian populations.
Bettuzzi observed that the Mediterranean diet is rich in vegetables, and lower rates of prostate cancer are found in that region, as well.
The 600 mg-per-day dosage of caffeine-free, total catechins (50 percent of which is EGCG) given to participants in the Italian study is one or two times the amount of green tea consumed daily in China, where ten to 20 cups a day is normal.
"We still don't know enough about the biological processes leading to prostate cancer," Bettuzzi noted. "The only thing we know for sure is that prostate cancer is diffuse, related to age and more prevalent in the West. Thus, prevention could be the best way to fight it. Although our follow-up will continue for up to five years, a larger, confirmatory study is needed."
Even so, Bettuzzi hints at the exciting prospect of using green tea catechins as a prophylactic against prostate cancer in men believed to be at higher risk, such as the elderly, African-Americans, and those with a family history of prostate cancer.
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