Preventive and therapeutic effects of green tea on lung cancer: a narrative review of evidence from clinical and basic research

BACKGROUND AND OBJECTIVE: Green tea is a popular beverage worldwide and has numerous health-promoting properties. Accumulating evidence indicates that green tea has preventive and therapeutic effects on lung cancer. This study aimed to investigate the association between green tea consumption and lung cancer. METHODS: We performed a narrative review to summarized the association between green tea consumption and lung cancer. KEY CONTENT AND FINDINGS: Green tea consumption is known to decrease lung cancer risk in the general population, as indicated by meta-analyses of observational studies. Two active components of green tea, theabrownin and (−)-epigallocatechin gallate (EGCG), mediate the antitumor activity of green tea. Theabrownin promotes apoptosis, induces cell cycle arrest, and inhibits the migration, clone formation, and proliferation of lung cancer cell lines in vitro and in vivo. EGCG inhibits lung cancer cell proliferation and promotes apoptosis, agenesis, and epithelial-mesenchymal transition (EMT). In addition, EGCG sensitizes lung cancer cells to cisplatin and tyrosine kinase inhibitors (TKIs). The possible molecular mechanisms underlying the antitumor activity of EGCG and theabrownin were reviewed. CONCLUSIONS: Observational studies have indicated that green tea has preventive effects on lung cancer. In vitro and animal studies have indicated that green tea has therapeutic effects on lung cancer. Further clinical trials are needed to illustrate the therapeutic effects of green tea or its active components (i.e., theabrownin, EGCG) on lung cancer.