Differences in composition and diversity of the gut microbiota of post-menopausal breast cancer patients

The gut microbiota colonizes the intestinal tract with essential roles in immune function, gut epithelial integrity, and metabolic signaling. To investigate the relationship between microbiota composition and breast cancer development, stool samples were collected from 27 treatment naïve post-menopausal breast cancer patients of varying hormone receptor statuses and 25 post-menopausal participants without breast cancer who served as controls. Samples from breast cancer patients and controls were compared for significant differences (p<0.05) in alpha and beta diversity. Significant differences in alpha diversity were observed between all breast cancer types compared to controls (padj=0.042), and between ER+Her2- breast cancer compared to controls (padj=0.006). Using principal coordinate analyses (PCA), significant differences in beta diversity were identified between all breast cancer types compared to controls (padj=0.048), and ER+Her2- breast cancer compared to controls (padj=0.036). Further analyses identified key microbiota genera of microbiota related to breast cancer development and progression. Notably, Akkermansia, a genus associated with gut barrier dysfunction, was reduced in ER+Her2- patients. Overall, this study reports on alterations in microbiota composition in stool samples from untreated postmenopausal breast cancer patients compared to control subjects. The data obtained could provide important insights into the association between altered microbiota and breast cancer progression and guide future patient screening and prevention efforts.