Intratumoral Microbiota: Unraveling their Oncogenic Impact on Cancer Progression With Focus on Breast Cancer Therapeutic Outcomes

The gut microbiota has been implicated in many cancers through the secretion of blood-traveling metabolites or activation of oncogenic signaling. Currently, specific microbial signatures have been detected in the human breast, which are different from other microbial-rich compartments, such as the intestine and skin. Changes in the breast microbiome profile have been shown to positively or negatively correlate with breast cancer development, progression, and therapeutic outcomes. However, studies regarding the role and underlying mechanism of intratumoral microbiota in breast cancer have remained concealed. This review aimed to provide an overview of the role of the intratumoral microbiome in tumorigenesis and tumor progression, and how these intratumoral microbiota affect breast cancer. We also discuss the potential of using the intratumoral microbiome as a biomarker or treatment alternative in breast cancers.