The role of probiotics in controlling oral biofilm formation and mitigating oral squamous-cell carcinoma risk.
This review examines the role of specific probiotic strains in modulating oral biofilms and immune pathways implicated in the prevention of oral squamous cell carcinoma (OSCC). Evidence indicates that Lactobacillus fermentum, L. salivarius, Bifidobacterium animalis, and Streptococcus salivarius effectively disrupt carcinogenic biofilms through multiple mechanisms. These include competitive exclusion, nutrient competition, and the production of antimicrobial peptides and biosurfactants. In addition, they contribute to cancer prevention by detoxifying mutagens such as acetaldehyde and nitrosamines. These probiotics also influence OSCC-relevant immunity by enhancing natural killer cell cytotoxicity, promoting CD8⁺ T-cell activity, and inducing TRAIL-mediated apoptosis, while strengthening epithelial defenses via upregulation of tight junction proteins. Multi-strain formulations frequently demonstrate superior efficacy compared to single strains, reflecting potential synergistic mechanisms. Nonetheless, outcomes remain highly strain-dependent and context-specific. Overall, current evidence suggests a promising yet preliminary role for probiotics in OSCC prevention, underscoring the need for rigorously designed, strain-specific clinical trials and optimized delivery systems tailored to the oral environment.