Two distinct microbiota are present in breast tissue samples, both tumor (<i>n</i> = 668) and NCA (<i>n</i> = 72).

<p>(A) Optimal <i>k</i>-cluster selection analysis demonstrating a majority decision among the 26 metrics for 2 clusters was concordant for both tissue cohorts identifying a systemic handling bias. (B) The t-SNE projections for the 668 tumors samples, demonstrating tissues demonstrating separation and cohesion among the batches. (C) Filtering was re-applied among the tissue samples and per processing differences. Venn diagram demonstrates a core 327 bacterial OTU’s was observed among all samples. (D) Abundance differences were observed for 48 OTU’s. A PCA plot of these significant OTU’s is presented demonstrating that the batch differences had been accounted for, NCA tissues indicated with an ‘N’ and tumor samples indicated with a ‘T’.