Scientists in the United States say they have shown that green tea extract can prevent the development of cancerous tumours without damaging healthy cells in a study of bladder cancer. The research team, led by Chinese-American scientists, believe green tea extract could be an effective anti-cancer drug.

The findings were published in the journal Clinical Cancer Research. Jianyu Rao, an associate professor at the University of California, Los Angeles, who led the study, said their results "advance the understanding of how green tea extract works". Understanding how green tea extract inhibits tumors could help determine which types of cancer patients benefit from it.

In their paper, the researchers wrote that the development of cancerous tumors is closely related to the movement of cancer cells, and for cancer cells to move, they must initiate a cellular process called actin remodeling. Once this process is activated, cancer cells are able to invade healthy tissue, causing tumors to spread. Green tea extract disrupts the "actin remodeling" process, which prevents cancer cells from sticking together and moving. It also causes cancer cells to age faster.

According to Rao, green tea extract breaks the aggressive path of cancer cells, limiting them and making them localized, making both cancer treatment and prognosis relatively simple.

Previous studies have shown that green tea extract has an effect on a number of cancers, including bladder cancer, by causing premature apoptosis of cancer cells and blocking the blood supply to tumour tissue. Rao told Xinhua that some members of his research team are testing the effect of green tea extract on other cancers, such as stomach cancer.

Unlike similar previous studies, he said, the green tea extract they used was very similar in composition to the green tea they drank, suggesting that regular green tea consumption may have some anti-cancer effect, at least by boosting the body's defenses against cancer. However, the researchers note that they only studied a limited number of bladder cancer cell lines so far, so more research is needed to reveal the anti-cancer mechanism of green tea.

Other scientists commented on the day that the findings further support the potential of green tea in preventing and treating cancer. Especially in the treatment of bladder cancer, the new results can help to identify those who are susceptible to bladder cancer and reduce its incidence.