Effect of gastrointestinal microbiome and its diversity on the expression of tumor‑infiltrating lymphocytes in breast cancer

The diversity of the gastrointestinal microbiome is closely associated with human health. In the present study, the gastrointestinal microbiome and tumor-infiltrating lymphocytes (TILs) were compared in patients with breast cancer (BC). A total of 80 patients with BC were divided into three groups based on the expression of TILs, as follows: High expression of TILs (TIL-H), medium expression of TILs (TIL-M) and low expression of TILs (TIL-L). DNA of the gastrointestinal microbiome was determined by Illumina sequencing and taxonomy of 16S ribosomal RNA genes. A (2) test and UniFrac analysis of -diversity were applied to assess the association between clinical characteristics and diversity of the gastrointestinal microbiome. The -diversity distribution was statistically significant (weighted UniFrac, P<0.01; unweighted UniFrac, P<0.01) when comparing the TIL-L and TIL-H groups and when comparing the three groups (TIL-H vs. TIL-M vs. TIL-L). At the genus level, higher abundances of Mycobacterium, Rhodococcus, Catenibacterium, Bulleidia, Anaerofilum, Sneathia, Devosia and TG5, but lower abundances of Methanosphaera and Anaerobiospirillum (P<0.05) were identified in the TIL-L group compared with the TIL-H group. At the species level, the stercoris, barnesiae, coprophilus, flavefaciens and C21_c20 species exhibited a higher abundance in the TIL-L group, whereas producta and komagatae exhibited a greater abundance in the TIL-H group (P<0.05). Collectively, the diversity of the gastrointestinal microbiome was associated with the expression of TILs in patients with BC.