Salivary IL-6 and Interleukin Gene Polymorphisms in Oral Squamous Cell Carcinoma

Inclusion Criteria: * Age 18 years or older * Histopathologically confirmed diagnosis of oral squamous cell carcinoma of the oral cavity * Oral squamous cell carcinoma site excluding oropharyngeal sites * Defined regional lymph node status allowing classification as OSCC N0M0 or OSCC N+M0 * Absence of distant metastasis, classified as M0 * Saliva sample collection feasible before any OSCC-specific oncological treatment, including surgery, radiotherapy, chemotherapy, immunotherapy, or targeted therapy * Suitability for saliva collection using a standardized absorbent swab * Availability of biological material for genotyping * Ability to provide written informed consent for study participation, biological sampling, and genetic analysis Exclusion Criteria: * Age younger than 18 years * Oral squamous cell carcinoma involving oropharyngeal sites * Presence of distant metastasis * Previous OSCC-specific oncological treatment before saliva sample collection * Acute infection at the time of sampling or within the previous 2 weeks * Active or inadequately controlled systemic autoimmune or inflammatory disease that may significantly alter cytokine profiles * Systemic immunosuppressive or immunomodulatory therapy within the previous 4 to 8 weeks * Recent oncological treatment for malignancies other than OSCC within the previous 6 months, if considered potentially interfering with the immune-inflammatory profile * Clinically significant acute oral infection or inflammatory process at …