There is no scientific evidence that regular consumption of green tea can prevent the development of cancer. In 2009, a review article was published, the purpose of which was to establish the relationship between green tea and various cancers, such as cancer of the intestine, prostate, breast, oral cavity and lungs. The authors of this review analyzed the results of more than 50 studies and concluded that "the presence of the desired relationship is unlikely." But the search did not end there: in 2015, scientists conducted a study of a substance obtained by combining an extract of green tea and herceptin – a drug that is actively used to treat cancer of the stomach and breast. The first laboratory tests were positive, but so far the scientific evidence to claim that consuming green tea during a Herceptin course will make treatment more effective is not enough.