Salivary microbial dysbiosis is associated with systemic immune factors in oral squamous cell carcinoma patients

This study investigates the alterations in the composition of the oral microbiome in individuals with oral squamous cell carcinoma (OSCC) and examine the relationship between the oral microbiome and immune-related variables in the tumor immunological microenvironment of the host. The expression levels of immune factors interleukin-2 (IL-2), interleukin-10 (IL-10), and interferon-γ (IFN-γ) in the peripheral blood of OSCC patients and healthy volunteers were investigated using the enzyme-linked immunosorbent test (ELISA). Saliva samples were obtained from both OSCC patients and healthy control participants. The bacterial 16SrRNA gene was then analyzed using high-throughput sequencing to compare the composition and quantity of oral flora between OSCC patients and healthy volunteers. The bacteria that exhibited notable differences were compared with each other. Analyzed the correlation between the systemic immunological state of the host. The serum levels of IL-2 and IFN-γ were significantly greater in the OSCC group compared to the healthy controls (HC) group (IL-2, P<.001, IFN-γ, P<.01). In contrast, the serum IL-10 expression level in the OSCC group was significantly lower than that in the HC group (P <.01). The bacterial genera that differ between the OSCC group and the HC group are associated with the host immunological markers. Peptostreptococcus exhibited a noteworthy positive correlation with IL-2, but Thermus demonstrated a negative correlation with IL-2. The presence of IL-10 was shown to be positively associated with the genera Oralobacter and negatively associated with the genus Eikenella. The genus Peptostreptococcus had a notable positive connection with IFN-γ and a negative correlation with unclassified Actinobacteria. Significant differences in immune factor expression and oral microbiota were found between OSCC patients and HC. Microbial dysbiosis, particularly involving Fusobacterium and Veillonella, may influence OSCC progression by modulating the immune microenvironment.