Advances in Understanding the Impact of Human Gut Microbiota on Chemotherapy-Induced Neutropenia

Neutrophils play a crucial role in defending against bacterial and fungal pathogens; however, chemotherapy reduces neutrophil counts, increasing infection risk and worsening cancer treatment outcomes. Emerging evidence highlights the gut microbiota as a promising biomarker and therapeutic target for chemotherapy-induced neutropenia (CIN). Here, we review current knowledge regarding the relationship between the gut microbiota and CIN, summarizing the mechanisms by which the microbiota influence neutrophil dynamics, current therapeutic approaches, and limitations in regard to preserving microbiota stability. This review offers a theoretical foundation for "gut-protective" chemotherapy, potentially facilitating personalized treatments, although clinical translation remains challenging.