Characterization of human breast tissue microbiota from core needle biopsies through the analysis of multi hypervariable 16S-rRNA gene regions

Breast microbiota compositions are not well understood, and a few recent reports have begun to explore the correlation between breast tissue dysbiosis and cancer. Given that various methods for breast microbiota detection were used, the aim of the present paper was to clarify which hypervariable region of the 16S-rRNA gene (V2, V3, V4, V6+7, V8, and V9) is the most informative for breast tissue microbiota. Core needle biopsies (CNBs) were compared with surgical excision biopsies (SEBs) to fnd a less invasive form of recovery useful for the analysis of a larger statistical population and potentially for diagnostic use of breast tissue microbiota. Finally, this study was the frst to analyse the breast microbiota of tumours and paired normal tissues of a Mediterranean population. Our fndings showed that the V3 region is the most informative for breast tissue microbiota, accounting for 45% of all reads. No signifcant diferences were found between CNB and SEB specimens in terms of total reads and numbers of Operational Taxonomic Units (OTUs). Moreover, we fnd that more similarities than diferences exist between tumours and adjacent normal tissues. Finally, the presence of the Ralstonia genus is associated with breast tissu