Saliva-Based Testing to Enable Early Detection of Cancer, Heart Disease or Parkinson’s

Saliva is one of the most accessible biological fluids, yet it remains underutilized in clinical practice. While saliva samples are used to perform genetic tests to determine, for example, paternity, the potential of saliva-based clinical analysis goes far beyond this, as shown in new research published in npj Genomic Medicine.

A research team at the University of the Basque Country (UPV/EHU, Biscay, Spain) analyzed saliva samples from more than 350 people and catalogued the common variations in DNA, known as genetic polymorphisms, or SNPs (single-nucleotide polymorphisms), that could influence genome function in saliva. Specifically, they found that these polymorphisms act as a switch that activates or deactivates the function of the genes they affect. Comparing the data from their study with the results of previous large international genetic studies on the risk of developing chronic diseases, they observed that many of the same polymorphisms that were detected in the saliva are associated with a higher risk of developing common diseases such as prostate cancer, coronary disease, Parkinson’s and Type 2 diabetes.

Image: Saliva still remains underutilized in clinical practice (Photo courtesy of UPV/EHU)

Furthermore, using advanced statistical tools, the research group demonstrated that these markers can explain a significant proportion of the genetic heritability of various diseases, in some cases with greater precision than traditional blood indicators. Although these findings need to be validated in larger cohorts for each of the diseases, they represent a significant advance in identifying non-invasive disease biomarkers. 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. Another contribution from this study is the creation of the largest public database of genetic data derived from saliva samples, which can be consulted via an open-access platform. The open-access nature of the database is expected to encourage new research studies and innovations in different biomedical disciplines.

“Our results show that molecular markers present in saliva can reflect systemic pathological processes beyond the oral cavity,” said José Ramón Bilbao, Professor of Medical Genetics at the EHU and one of the lead authors of the study.

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