The The use of saliva as a diagnostic tool in Oral Squamous Cell Carcinoma: an integrative review of clinical, molecular, and prognostic biomarkers

Abstract

Introduction: Oral squamous cell carcinoma (OSCC) is the most frequent type of malignant neoplasm in the oral cavity; it is generally diagnosed at advanced stages, which worsens the prognosis. In this context, saliva presents itself as a promising tool due to its ability to provide biomarkers associated with disease development and monitoring, addressing the need for early, non-invasive, and accessible diagnostic methods. Methodology: This study is an integrative literature review that analyzed the role of biomarkers in the diagnosis, prognosis, and monitoring of the disease. The search was conducted in the PubMed/MEDLINE, SciELO, Scopus, and Web of Science databases, covering studies published between 2017 and 2026. The selection included observational studies, diagnostic accuracy studies, clinical trials, methodological studies, validation studies, systematic reviews, and meta-analyses, as well as an epidemiological study for contextualization. Data synthesis was performed qualitatively and comparatively. Results and discussion: A total of 261 studies were identified, 13 of which met the eligibility criteria. The results showed that salivary biomarkers—such as proteins, nucleic acids, and metabolites—hold significant potential for early diagnosis, risk stratification, and disease monitoring, demonstrating satisfactory sensitivity and specificity, especially when used in combination. However, their clinical application remains limited by factors such as methodological heterogeneity, small sample sizes, and a lack of standardization in collection and analysis methods. Conclusion: In this context, salivary biomarkers emerge as a promising, non-invasive, and low-cost option capable of contributing to the early detection and clinical monitoring of oral squamous cell carcinoma. Nevertheless, they should be employed as a complement to conventional diagnostic methods, although they still require validation through multicenter studies.