Bacterial metabolites: Effects on the development of breast cancer and therapeutic efficacy (Review)

Evidence suggests that various gut metabolites significantly impact breast cancer (BC) and its treatment. However, the underlying mechanisms remain poorly understood and require further investigation. In the present study, the current literature was reviewed to evaluate the roles of microbial metabolites in the development of BC and its response to treatment. Microbial metabolites, including secondary bile acids, short‑chain fatty acids, amino acid metabolites, lipopolysaccharide, nisin and pyocyanin, serve crucial roles in the BC microenvironment. Microbial metabolites promote BC invasion, metastasis and recurrence by facilitating cellular movement, epithelial‑mesenchymal transition, cancer stem cell function and diapedesis. Furthermore, certain metabolites, such as trimethylamine N‑oxide and L‑norvaline, can alter the pharmacokinetics of chemotherapeutic drugs. The present review highlights the possible involvement of microbial metabolites and bacteriocins in BC carcinogenesis, development and metastasis. These metabolites could provide new insights for BC treatment strategies and are considered potential therapeutic targets.