Saliva-Based Biomarkers in Oral Squamous Cell Carcinoma Using OMICS Technologies: A Systematic Review

(1) Background: Head and neck cancer (HNC) is a major public health challenge worldwide, with oral squamous cell carcinoma (OSCC) being the predominant form. Despite advances in treatment, OSCC remains a major cause of morbidity and mortality due to delayed diagnosis and limited therapeutic efficacy. This study reviews omics technologies to assess new salivary biomarkers for the early detection of OSCC. (2) Methods: A comprehensive literature search in the last 20 years identified four relevant studies focusing on salivary biomarkers in OSCC. (3) Results: Proteomic and genomic analyses revealed significant changes in salivary composition between OSCC patients and healthy controls, suggesting promising diagnostic and prognostic biomarkers. However, studies showed varying degrees of bias, indicating the need for further research and improved standardization. (4) Conclusions: Saliva, with its advantages of ease of collection, minimal invasiveness, and potential for large-scale screening, is an emerging promising substrate for non-invasive biomarker research. Nonetheless, there is a need for improved biomarker sensitivity and specificity; currently, histological examination remains the golden standard.