Saliva as a Diagnostic Medium: Biomarker Identification, Genetic Analysis, and Disease Association

Usha Subbiah¹*, Harini Venkata Subbiah¹, Sumathi K², Shenbaga Lalitha S²

Saliva acts as a non-invasive, cost-effective medium for diagnosing diseases, enabling biomarker identification, genetic analysis, and monitoring systemic health.

Abstract

Background: Saliva, an exocrine secretion, plays a vital role in maintaining oral and systemic health through its diverse molecular composition, including proteins, nucleic acids, and hormones. As an easily accessible and non-invasive biological fluid, saliva has emerged as a promising tool for diagnostic purposes, offering a potential medium for biomarker identification in various diseases. Methods: This review synthesizes current research on the use of saliva as a diagnostic medium, focusing on its molecular composition, including DNA, RNA, proteins, and noncoding RNAs, and their applications in disease diagnosis. We explore the use of salivary biomarkers in the detection of oral and systemic diseases, such as oral squamous cell carcinoma (OSCC), diabetes mellitus, cardiovascular diseases, and genetic disorders. The review also discusses the role of genetic polymorphisms in salivary proteins and their association with disease risk, as well as the potential of saliva in detecting infectious diseases like COVID-19, dengue, and HIV. Results: Salivary biomarkers, including DNA, mRNA, noncoding RNAs, and proteins, have shown promise in diagnosing a range of diseases. Studies have identified specific salivary mRNAs, such as IL-6 and NGFI-A binding protein 2, as potential biomarkers for OSCC. Noncoding RNAs, including miRNAs and piRNAs, have been implicated in various malignancies and systemic diseases. Proteomic analyses of saliva have revealed disease-specific protein signatures, providing insights into conditions such as Sjögren's syndrome, graft-versus-host disease, and diabetes. Furthermore, genetic polymorphisms in salivary proteins have been associated with oral diseases, such as dental caries and periodontitis, as well as systemic conditions. Conclusion: Saliva represents a valuable and underutilized diagnostic medium with the potential to revolutionize disease detection and monitoring. The identification of salivary biomarkers and genetic polymorphisms linked to disease risk underscores the importance of saliva in personalized medicine. However, further research is needed to standardize saliva collection and processing methods to enhance its diagnostic accuracy and reliability. The integration of salivary diagnostics into clinical practice could significantly improve patient outcomes through early detection and personalized treatment strategies.

Keywords: Salivary biomarkers, Genetic analysis, Non-invasive diagnostics, Oral diseases, Systemic health

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