Microbiome Crosstalk Across Oral, Gut, and Breast Niches: Implications for Breast Cancer Diagnosis, Prevention, and Therapy.

Breast cancer is a leading cause of morbidity and mortality in women worldwide. Breast tissue, oral and gut microbiota, are actively involved in regulating tumor onset, progression, and treatment response. Multiple factors, including ethnicity, sex, disease subtype, and stage, influence their signatures. The oral-gut-breast microbiome tripartite axis influences breast cancer by inducing DNA damage, altering the host immune response, and activating or suppressing cell-signaling processes through regulation of hormones, metabolites, and inflammatory markers. Modulating microbial homeostasis through diet, selective depletion of causative bacteria, and precise delivery techniques, such as nanotechnology, for delivering bioengineered microbes or microbial cargo, are among the recent therapeutic approaches with potential. However, generalizing findings and standardizing clinical regimens across diverse populations remains a persistent challenge. This review highlights the importance of microbiome-informed, integrated strategies for enhancing breast cancer prevention, diagnosis, and treatment by exploring the causal and mechanistic microbial trends.