The Role of Micro biota in Breast Cancer Development, Progression, and Treatment Response: Mechanisms, Therapeutic Implications, and Future Directions

Breast cancer remains one of the leading causes of cancer-related mortality in women worldwide, with its development, progression, and treatment response influenced by a multitude of genetic, hormonal, and environmental factors. Recent evidence has unveiled a critical yet underexplored player in breast cancer pathophysiology the micro biota. The human micro biome, particularly the breast and gut micro biota, has emerged as a key modulator of tumor genesis through mechanisms involving chronic inflammation, immune regulation, microbial metabolite production, and epigenetic modifications. Dysbiosis, characterized by an imbalance in microbial composition, has been implicated in carcinogenesis by promoting DNA damage, altering estrogen metabolism, and shaping the tumor microenvironment to favor immune evasion and metastasis. This review provides a comprehensive analysis of the intricate interplay between micro biota and breast cancer at multiple levels, from disease initiation to therapeutic resistance. We explore how specific microbial populations influence treatment efficacy, including chemotherapy, hormone therapy, immunotherapy, and radiotherapy.