This article discusses the potential of saliva diagnostics for the non-invasive detection of systemic diseases and lung cancer, highlighting ongoing research and the benefits of using saliva as a diagnostic tool.

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.[1]

“In this current era of precision medicine and personalised medicine, the ability to utilise 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.[2]

Every day, the body produces between 0.5 and 1.5 litres of saliva.[3] Roughly 70% of the salivary genome is of human origin, while 30% is from the oral microbiota.[4][5]

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 tumour markers.[3] The Food and Drug Administration (FDA) has granted emergency authorisation for saliva tests to detect COVID-19.[6]

“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.[1]

“Saliva [diagnostic test] is non-invasive; it comes to the oral cavity non-invasively, non-painfully, and non-embarrassingly. Doctors, or the person himself] or herself, could harness this fluid and monitor it. Do I have the earliest indication of disease X? Lung cancer or metabolic disease?” Dr. Wong says.

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.

However, 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.”

Disclaimer: This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.