Microbiome as prognostic indicator in oral cancer.

OSCC affects over 377,000 patients annually with poor prognosis. While conventional prognostic indicators like TNM staging provide structural information, they inadequately explain clinical outcome variability. The oral microbiome has emerged as a dynamic prognostic factor offering functional insights through non-invasive sampling and longitudinal monitoring. Specific microbial signatures strongly associate with clinical outcomes. Pathogens including Fusobacterium nucleatum, Porphyromonas gingivalis, Eubacterium, and Lactobacillus correlate with increased recurrence and reduced survival, while commensals like Veillonella, Streptococcus, and Staphylococcus predict favorable outcomes. Microbiome-based models outperform traditional parameters in recurrence stratification, with beta diversity distinguishing recurrent from non-recurrent cases. Functional pathways involving PI3K/AKT/mTOR signaling and immunomodulation demonstrate prognostic relevance. High-risk patterns promote immune evasion through CD8+ T-cell depletion, while favorable patterns maintain anti-tumor immunity. The microbiome influences treatment response, with dysbiosis reducing therapy effectiveness and increasing mucositis. Probiotic interventions show promise in restoring diversity and improving outcomes. Despite standardization challenges, the oral microbiome represents a promising non-invasive prognostic indicator for refining risk stratification and personalizing OSCC management.