Dynamic Changes of Dental Plaque and Saliva Microbiota in OSCC Progression

Objectives To elucidate the microbial and genomic changes in saliva and dental plaque during Oral Squamous Cell Carcinoma (OSCC) progression, and to identify potential mechanisms and virulence factors involved in OSCC pathogenesis. Materials and Methods Using metagenomic sequencing, 64 saliva and dental plaque samples from OSCC patients at different stages of differentiation were examined. Results The results showed notable differences in the microbial composition and genomic profiles across ecological regions and differentiation degrees. Notably, the relative abundance of specific microbes, such as Porphyromonas gingivalis , Fusobacterium nucleatum , and Haemophilus parainfluenzae , increased in poorly differentiated OSCC. Microbial alpha diversity in dental plaque and saliva correlates with tumor T staging. Dental plaque microbiota shows higher specialization, especially in poorly differentiated tumors. Both microbiota types become more stable with advanced T staging. Genomic analysis reveals increased virulence factors in poorly differentiated stages. Subsequently, functional pathway analysis and tracing of pathogens reveal specific microbial mechanisms in oral cancer pathogenesis. Oral pathogens may promote tumorigenesis by secreting factors like GAPDH, GspG, and AllS, and drive tumor initiation and progression through microbial interactions. Conclusions OSCC progression is associated with altered microbial composition, diversity, and genomic profiles in saliva and dental plaque. Poorly differentiated stages show higher abundance of pathogens and virulence factors, implicating them in tumorigenesis. Clinical Relevance Understanding microbial and genomic changes in saliva and dental plaque during OSCC progression could help develop new diagnostic biomarkers and therapies targeting the oral microbiota, potentially improving early detection, treatment efficacy, and prognosis for patients. Maintaining oral microbiome homeostasis may also help prevent oral cancer.