According to a study, presented at the American Association for Cancer Research annual meeting, green tea actually blocks the effect of bortezomib (Velcade) and other anticancer drugs. Researchers from the University of Southern California showed that polyphenol compounds in green tea possess so-called 1,2-benzene-diol moieties that chemically interact with bortezomib. As a result, in cancer cells treated with both green tea and bortezomib, the drug did not cause tumor cell death.