Gut and oral microbial compositional differences in women with breast cancer, women with ductal carcinoma <i>in situ</i>, and healthy womenOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study characterized and compared the fecal and oral microbiota of women newly diagnosed with early-stage breast cancer (BC), women with ductal carcinoma in situ (DCIS), and healthy women. Samples were collected before any cancer therapy and analyzed using 16S rRNA sequencing. The researchers examined microbial diversity, community composition, bacterial guild clustering, and predicted functional pathways in both gut and oral samples.
Who was studied?
The study population consisted of women with early-stage breast cancer, women with ductal carcinoma in situ, and healthy women who served as controls. Samples were collected from newly diagnosed patients prior to any treatment, meaning the microbiota data reflect an untreated disease state. The abstract does not give exact numbers of participants, so specific cohort sizes cannot be reported.
What were the most important findings?
Gut microbial alpha diversity was significantly lower in the breast cancer group compared to healthy women, and beta diversity differed significantly between the breast cancer or DCIS groups and healthy controls. Clustering identified five gut bacterial guilds dominated by Prevotella, Enterobacteriaceae, Akkermansia, Clostridiales, or Bacteroides, with the Bacteroides and Enterobacteriaceae guilds more abundant in breast cancer patients and the Clostridiales guild more abundant in healthy women. Predicted functional pathway analysis identified 23 pathways that differed between groups, including lipopolysaccharide biosynthesis, glycan biosynthesis and metabolism, lipid metabolism, and sphingolipid metabolism. In contrast, the oral microbiome showed no significant differences in alpha or beta diversity between groups.
What are the greatest implications of this study?
The findings suggest that gut, but not oral, microbial composition is altered in women with early-stage breast cancer relative to healthy women, pointing to the gut as a more relevant site for microbiome-cancer associations. The shifts toward Bacteroides and Enterobacteriaceae dominance and away from Clostridiales, along with altered lipid and glycan metabolism pathways, suggest possible mechanistic links between gut dysbiosis and breast cancer biology. These results support further investigation of the gut microbiome as a potential biomarker or contributor to breast cancer risk, warranting studies with larger cohorts to confirm causality.