Imagine a world in which a simple saliva swab could save lives. Researchers say that in the not too distant future, this could be a reality.

Researchers say that saliva diagnostics may soon be used in the detection of systemic diseases and cancer.

Nonaka T, Wong DTW. Saliva Diagnostics. Annual Review of Analytical Chemistry. 2022;15(1):107-121.

 

“In this current era of precision medicine and in personalized medicine, the ability to utilize these bodily constituents—the omics constituents, so to speak, that [are] circulating in our body fluid—and harness this information for health surveillance for disease detection, it's here in front of us,” David T.W. Wong, Director of the UCLA Center for Oral/Head & Neck Oncology Research (COOR) tells MDLinx.

Wong’s lab is pioneering research in the area of saliva diagnostics, in the hopes that a simple test could be used in the early detection of diseases like lung cancer.

UCLA School of Dentistry. David Wong Lab.

 

Every day, the body produces between 0.5 and 1.5 liters of saliva.

Ghannam MG, Paramvir Singh. Anatomy, Head and Neck, Salivary Glands. NIH. 4. Fabian T, Fejerdy P, Csermely P. Salivary Genomics, Transcriptomics and Proteomics: The Emerging Concept of the Oral Ecosystem and their Use in the Early Diagnosis of Cancer and other Diseases. Current Genomics. 2008;9(1):11-21.

 

Roughly 70% of the salivary genome is of human origin, while 30% is from the oral microbiota.[4]

There are numerous biocomponents contained in saliva that may act as biomarkers, including various proteins (amylase, lactoferrin, mucins, and others); antibodies (IgA); viruses; bacteria; both human and microbial DNA, mRNA, and tumor markers.

Ghannam MG, Paramvir Singh. Anatomy, Head and Neck, Salivary Glands. NIH. 4. Fabian T, Fejerdy P, Csermely P. Salivary Genomics, Transcriptomics and Proteomics: The Emerging Concept of the Oral Ecosystem and their Use in the Early Diagnosis of Cancer and other Diseases. Current Genomics. 2008;9(1):11-21.

 

The Food and Drug Administration (FDA) has granted emergency authorization for saliva tests to detect COVID-19.

Food and Drug Administration. Coronavirus (COVID-19) Update: FDA Issues Emergency Use Authorization to Yale School of Public Health for SalivaDirect, Which Uses a New Method of Saliva Sample Processing. August 15, 2020.

 

“COVID brought saliva to the forefront of molecular diagnostics globally. This pathogen, SARS-CoV-2, presents itself in this fluid, just like it is in blood…but you can detect it in saliva, and with the benchmarking against nasal swab just as good, if not better,” Dr. Wong says.

Some of the benefits of using saliva in diagnostics include ease of access to samples, a noninvasive method of sample collection, and increased patient acceptance.

Nonaka T, Wong DTW. Saliva Diagnostics. Annual Review of Analytical Chemistry. 2022;15(1):107-121.

 

Dr. Wong’s lab is currently working on using saliva diagnostics to detect lung cancer. Twelve years ago, Dr. Wong’s group established that the malignancy ‘fingerprints’ of lung cancer could be detected in saliva.

“Detecting these ‘fingerprints’ of lung cancer in saliva, it's cleaner, meaning it has a better performance than detecting them in blood,” Dr. Wong notes.

Research on indeterminate pulmonary nodules is now underway.

“You find a mass in the lung…however, when you detect it, you don't know if it’s cancer or not. This patient has to go [and] come back with a second screen. If the lesion gets bigger, then you biopsy; if not, you watch and wait. We are currently working on this exact project at the time of lesion detection. In addition to having this patient go back and come back in 6 months, we take a drop of their blood and saliva, and we look for those ‘fingerprints’ at the time of lesion detection. If we find those ‘fingerprints,’ this patient will be biopsied So they don't have to go back, we can find their malignancy ‘fingerprints,’” Dr. Wong explains.

“These ‘fingerprints’ that are unique to lung cancer are druggable. You can treat them [the] moment you see these ‘fingerprints’—by third generation TKI that can extend the lifespan of this patient up to 2 years. Isn't that a great thing?” Dr. Wong adds.

While research on the use of saliva diagnostics for systemic disease detection is ongoing and currently in its infancy, it adds to a growing body of research into liquid biopsy.

“Liquid biopsy is just at the frontier right now. That is just tremendously impactful and significant. And we're in that particular landscape to advance this field and, importantly, perhaps, positioning saliva in that frontier,” Dr. Wong says.

He argues that more research is needed to provide the scientific basis necessary for regulatory approvals that would allow saliva tests to be used to detect diseases like lung cancer.

But Dr. Wong is optimistic that the use of saliva diagnostics has the potential to save lives.

“Let the science talk. And, if at the end of the day, saliva has unique opportunities and performance that perhaps surpasses that of taking a spinal tap to detect a neurological disorder—and you can detect these same targets with performance that outperform[s] the current practice—that's what we look forward to.”