Intra-tumoral microbial community profiling and associated metabolites alterations of TNBC

Triple-negative breast cancer (TNBC) presents significant challenges to femalehealth owing to the lack of therapeutic targets and its poor prognosis. In recentyears, in the field of molecular pathology, there has been a growing focus on therole of intra-tumoral microbial communities and metabolic alterations in tumorcells. However, the precise mechanism through which microbiota and theirmetabolites influence TNBC remains unclear and warrants further investigation.In this study, we analyzed the microbial community composition in varioussubtypes of breast cancer through 16S rRNA MiSeq sequencing of formalin-fixed,paraffin-embedded (FFPE) tissue samples. Notably, Turicibacter, a microbeassociated with cancer response, exhibited a significantly higher abundance inTNBC. Similarly, mass spectrometry-based metabolomic analysis revealedsubstantial differences in specific metabolites, such as nutriacholic,pregnanetriol, and cortol. Furthermore, we observed significant correlationsbetween the intra-tumoral microbiome, clinicopathological characteristics,and human epidermal growth factor receptor-2 expression(HER2). Threemicrobial taxa (Cytophagaceae, Conexibacteraceae, and Flavobacteriaceae)were associated with tumor-infiltrating lymphocytes(TILs), which are indicativeof antitumor immunity. This study creatively utilized FFPE tissue samples toassess intra-tumoral microbial communities and their related metaboliccorrelations, presenting avenues for the identification of novel diagnosticbiomarkers, the development of therapeutic strategies, and the early clinicaldiagnosis of TNBC.