Insights into the gut microbiome-metabolite dynamics in breast cancer

In recent years, understanding the intricate connection between gut microbiome and cancer development has gained significant attention. The gut microbiome has a key role in maintaining overall human health and modulating the body's defense mechanism against various diseases. This review examines the multifaceted association between the gut microbiome and breast cancer, providing a comprehensive overview of studies from the last two decades that investigate both anti-cancer and pro-cancer properties of gut metabolites. Compounds such as nisin, inosine, acetate, propionate, and conjugated linoleic acids have demonstrated potential as therapeutic agents against breast cancer, while others, including butyrate, lactate, certain bile acids, and secondary metabolites, exhibit dual roles, showing both anti-cancer and pro-cancer properties under different conditions, with some implicated in tumor progression. Moreover, emerging research highlights the dual roles of these metabolites in influencing the efficacy of conventional breast cancer therapies. Despite promising evidence, the molecular mechanisms underlying these opposing actions remain unclear and require further investigation. To advance our understanding, future research should prioritize elucidating these mechanisms, establishing dose-response relationships, and conducting animal and clinical studies to validate in vitro findings. This review also identifies key gaps and highlights potential directions for future research in this field.