In a groundbreaking advancement poised to redefine clinical diagnostics, researchers from the University of the Basque Country (EHU) have unveiled compelling evidence supporting the use of saliva as a rich and accessible source of molecular biomarkers that extend far beyond oral health conditions. Traditionally overshadowed by blood as the standard medium for genetic and molecular analysis, saliva is emerging as a transformative diagnostic fluid thanks to its non-invasive collection, ease of handling, and the wealth of genetic information it harbors.
Professor José Ramón Bilbao, a leading geneticist at EHU and co-lead author of this pivotal study, emphasizes the underappreciated potential of saliva in medical diagnostics. “Saliva is one of the most accessible biological fluids but it is still underutilised in clinical practice,” he explains. The research highlights that saliva contains molecular markers reflective of systemic pathological processes, which means it could serve as a window into diseases affecting organs and tissues far beyond the oral cavity.
The scientific team meticulously analyzed saliva samples obtained from over 350 individuals, focusing on the cataloging of single nucleotide polymorphisms (SNPs)—the minute variations in DNA sequence known to influence gene function. Their approach concentrated on determining how these polymorphisms, essentially genetic switches, modulate gene activity. These SNPs were found not just to exist in saliva but to exert functional effects that parallel those identified in blood-based studies of genome function and disease susceptibility.
A striking outcome of the research was the demonstration that many of the SNPs detected within saliva samples are significantly associated with an elevated risk for a multitude of common chronic diseases. These include, but are not limited to, prostate cancer, coronary artery disease, Parkinson’s disease, and Type 2 diabetes. This observation aligns with large-scale international genome-wide association studies (GWAS) previously conducted on blood-derived DNA, thereby validating saliva as an equivalent medium for detecting disease-relevant genetic variants.
Beyond identifying risk-associated polymorphisms, the scientists employed sophisticated statistical modeling to assess the contribution of saliva-based genetic markers to heritability estimates of complex diseases. Intriguingly, their analyses revealed that saliva-derived SNPs could explain a considerable portion of genetic heritability, in some instances outperforming traditional blood biomarkers. This raises the prospect of saliva potentially offering more precise genetic risk stratification in clinical settings.
While the research is poised to revolutionize non-invasive diagnostics, the investigators underscore the necessity for validation in expanded cohorts and diverse populations to fully establish clinical utility. Alba Hernangómez-Laderas, a molecular biologist and co-lead on the project, underscores this point: “This work opens the door to developing saliva-based testing that could in the future be used for the early detection of diseases or for monitoring treatments, without the need to extract blood or perform other invasive procedures.”
The implications of this work are both profound and practical, predicting a future where saliva-based tests become routine tools in preventive medicine and personalized healthcare. The minimal discomfort and ease of repeated sample acquisition position saliva as an ideal biofluid for longitudinal monitoring of disease progression and therapeutic response, potentially reshaping patient compliance and engagement.
An additional cornerstone of the study was the development of the largest publicly accessible genetic database derived from saliva samples. Hosted via an open-access platform, this genetic repository is designed to stimulate innovative research and foster collaboration across biomedical disciplines. Researchers worldwide will be able to leverage this resource to explore novel diagnostic markers and genetic architectures of disease.
This research forms part of a collaborative effort involving eight additional researchers from EHU and partnering institutions including BioGipuzkoa, BioBizkaia, and the Icahn School of Medicine at Mount Sinai in New York. The interdisciplinary nature of the team reflects the complexity of translating molecular genetic discoveries into clinical practice, weaving together expertise from genomics, biostatistics, and clinical medicine.
At its core, this study challenges the current paradigm that prioritizes blood samples for genome-based diagnostics. By demonstrating that saliva harbors equivalent or superior genetic information relevant to systemic diseases, it lays the groundwork for more accessible, cost-effective, and patient-friendly diagnostic methodologies. Such progress aligns with the global pursuit of precision medicine, where non-invasive, rapid, and accurate testing modalities are paramount.
The potential for saliva to act as a diagnostic medium is particularly timely given the ongoing push toward decentralized healthcare and community-based testing facilities. Saliva’s collection simplicity obviates the need for trained phlebotomists and stringent cold-chain logistics, thereby broadening access to genetic testing in underserved or remote areas, and enabling large-scale screening programs.
As exciting as these findings are, the authors caution that rigorous longitudinal studies and regulatory evaluations are required before saliva-based genetic tests can be incorporated into routine clinical protocols. Nonetheless, the foundational data generated by this study constitute a significant leap forward, elevating saliva from a diagnostic curiosity to a bona fide molecular goldmine.
In summary, this pioneering research underscores saliva’s vast promise as a non-invasive, informative, and practical surrogate for blood in genomic medicine. The identification of functional DNA methylation biomarkers within saliva heralds a new era for the early detection and management of multifactorial diseases, leveraging the genetic fingerprints embedded in our most accessible bodily fluid.
Subject of Research: Saliva as a diagnostic medium for DNA methylation biomarkers indicating disorders beyond oral health
Article Title: Saliva as a potential diagnostic medium: DNA methylation biomarkers for disorders beyond the oral cavity
News Publication Date: 20-Jun-2025
Web References:
https://doi.org/10.1038/s41525-025-00509-0
References:
Alba Hernangómez-Laderas, Ariadna Cilleros-Portet, Sergi Marí, Bárbara P. González-García, Ane Arregi, Alba Jimeno-Romero, Amaia Irizar, Iraia García-Santisteban, Corina Lesseur, Nora Fernandez-Jimenez, José Ramón Bilbao. Saliva as a potential diagnostic medium: DNA methylation biomarkers for disorders beyond the oral cavity. npj Genomic Medicine, 10, 49 (2025).
Image Credits:
Photo: Egoi Markaida. EHU
Keywords:
Saliva, Body fluids, Cancer, Cancer research, Heart disease, Parkinson’s disease
