Characterization of Gut Microbiome Composition in Patients with Triple-Negative Breast Cancer Treated with Neoadjuvant Chemotherapy

Abstract Introduction Patients with triple-negative breast cancer (TNBC) achieving a pathological complete response (pCR) after neoadjuvant chemotherapy have a better event-free survival. The role of gut microbiome in early TNBC is underexplored. Methods Microbiome was analyzed by 16SrRNA sequencing. Results Twenty-five patients with TNBC treated with neoadjuvant anthracycline/taxane-based chemotherapy were included. Fifty-six percent achieved a pCR. Fecal samples were collected before (t0), at 1 (t1), and 8 weeks (t2) from chemotherapy. Overall, 68/75 samples (90.7%) were suitable for microbiome analysis. At t0, pCR group showed a significantly higher α-diversity as compared with no-pCR, (P = .049). The PERMANOVA test on β-diversity highlighted a significant difference in terms of BMI (P = 0.039). Among patients with available matched samples at t0 and t1, no significant variation in microbiome composition was reported over time. Conclusions Fecal microbiome analysis in early TNBC is feasible and deserves further investigation in order to unravel its complex correlation with immunity and cancer. The gut microbiome has gained attention as a potential biomarker in patients with cancer; however, little is known about the role of gut microbiome in modulating response to standard neoadjuvant chemotherapy in patients diagnosed with early stage triple-negative breast cancer (TNBC). This article assesses the feasibility of gut microbiome analysis in patients undergoing neoadjuvant chemotherapy for early stage TNBC, evaluates its impact on treatment response and association with clinicopathologic factors, and describes longitudinal changes before and after exposure to chemotherapy.