The Oral Microbiome in Oral Cavity Cancer: Mechanisms of Carcinogenesis, Biomarkers, and Therapeutic Implications

Oral cavity cancer (OCC) is a significant clinical challenge within head and neck oncology. It is characterized by significant morbidity, high recurrence rates, and only modest improvements in long-term survival over recent decades. Recent advances in metagenomics and high-throughput sequencing have revealed that oral microbial dysbiosis contributes to tumorigenesis, highlighting the potential of microbiome-derived biomarkers for early detection and prognosis of OCC. The purpose of the work is to discuss oral microbiome alterations in OCC. The microbiome plays a crucial role in regulating the host's physiological, immunological, and metabolic functions. Changes in the composition of the microbiome can influence our health status of local diseases of the oral cavity and oropharynx, as well as systemic diseases. In recent years, the role of the oral microbiome in oral potentially malignant disorders progression and OCC development has been emphasized. Changes in the oral and gut microbiome can lead to the induction of chronic inflammation, modulation of the immune system, and the production of carcinogenic metabolites. Dysbiosis can lead to critical inflammatory responses and consequently contribute to neoplastic events. Microbiome-modulating therapies tailored to the patient's individual profile and aimed at improving cancer treatment outcomes are being introduced, including the introduction of antibiotics to reduce harmful bacteria. Identification of new biomarkers in oral microbiota communities and development of therapeutic strategies in relation with oral microbiota in the future may be one of the pillars of the oral cancer diagnosis and treatment strategy. Oral cancer prevention protocols should include the improvement of oral hygiene as an element of the prevention and treatment of periodontitis. An introduction of microbiota-targeted interventions, including probiotics, prebiotics, and dietary strategies, may reduce the toxicity of radiotherapy, leading to improved patient outcomes.