Targeting intratumor microbiota in oral squamous cell carcinoma from potential mechanisms to future opportunities

Abstract Oral squamous cell carcinoma (OSCC) is the predominant subtype of oral cancer, accounting for over 90% of all cases, with high incidence and poor long-term survival. Advances in the etiology of OSCC and ongoing characterization of the microbiota have revealed a strong association and interplay between intratumor microbiota and tumor evolution and treatment response. To deepen the current understanding of intratumor microbiota, this review summarizes changes in relative abundances of intratumor microbiota in OSCC, with a particular emphasis on the high abundance of specific species. Furthermore, we focus on microbiota-mediated signaling pathways involved in promoting cancer progression and explore possible direct and indirect mechanisms of microbiota-host interactions. Additionally, we discuss clinical applications related to cancer progression and treatment response, including diagnostics and therapeutic strategies, which might offer an optimal outlook for future individualized clinical treatment targeting intratumor microbiota in OSCC.