Figure 1.

Microbiota-host interactions in local intestine and distant breast. Gut microbiota influence amino acid bioavailability, metabolites (such as secondary bile acids, SCFAs), and PAMPs. Maternal milk plays an important role in establishing the gut bacterial system of the infant. Intestinal dysbiosis is associated with dysfunctions of estrogen enterogastric circulation, altered immunity, and inflammation of the host (TLRs, cytokines). However, the role of intestinal microbiota translocation between the gut and breast in the development and progression of breast disease is still unknown. All of these factors could potentially influence pathogenesis and progression of breast cancer and other breast diseases.