Saliva Test Improves Oropharyngeal Cancer Detection

Dentistry Today


Cancers in the back of the mouth and the upper throat often aren’t diagnosed until they reach their advanced stages because their location makes them difficult to see during routine clinical exams. An international team of researchers, however, is using acoustofluidics to non-invasively analyze saliva for the presence of human papillomavirus 16 (HPV-16), the pathogenic strain associated with oropharyngeal cancers (OPCs). In fact, this technique has detected OPC in whole saliva in 40% of patients tested and in 80% of confirmed patients.

“OPC has an approximate incidence of 115,000 cases per year worldwide and is one of the fastest rising cancers in Western countries due to increasing HPV-related incidence, especially in younger patients. It is paramount that surveillance methods are developed to improve early detection and outcomes,” said co-lead investigator Tony Jun Huang, PhD, of the Duke University Department of Mechanical Engineering and Materials Science

Considering these factors, the successful detection of HPV from salivary exosomes isolated by our acoustofluidic platform offers distinct advantages, including early detection, risk assessment, and screening,” said Huang, adding that this technique also may help physicians predict which patients will respond well to radiation therapy or achieve longer progression-free survival.

Exosomes are tiny microvesicles originating within cells that are secreted into body fluids. They are believed to play a role in intercellular communication, and their numbers are elevated in association with several types of cancers. Fusing acoustics and microfluidics, acoustofluidics analyzes fluid samples using a tiny chip developed to isolate salivary exosomes by removing unwanted particles based on size. This leaves exosome-rich concentrated samples that make it easier to detect tumor-specific biomarkers. 

In their study, the researchers analyzed saliva samples from 10 patients diagnosed with HPV OPC using traditional methods. They found that the technique identified the tumor biomarker HPV-16 DNA in 80% of the cases when coupled with droplet digit PCR. Since this method is independent of sample variability that arises due to changes in saliva viscosity and collection methods used, it may prove ideal for use in clinical settings, the researchers said. 

The technique offers automated and fast exosome isolation, with less than five minutes of processing time compared to approximately eight hours of processing time using benchmark technologies. Analyses can be performed at relatively low cost and at points of care, Huang said. Also, it is suitable for repeated and continuous monitoring of tumor progression and treatment, unlike traditional biopsies.

“With these features, the acoustofluidic technology has the potential to significantly exceed current industry standards, address unmet needs in the field, help expedite exosome-related biomedical research, and aid in the discovery of new exosomal biomarkers,” said Huang.

“The saliva exosome liquid biopsy is an effective early detection and risk assessment approach for OPC,” said co-lead investigator David TW Wong, DMD, DMSc, of the Center for Oral/Head and Neck Oncology Research at the University of California Los Angeles School of Dentistry. “The acoustofluidic separation technique provides a fast, biocompatible, high-yield, high-purity, label-free method for exosome isolation from saliva.”

According to the researchers, this technology can also be used to analyze other biofluids such as blood, urine, and plasma.

The study, “Acoustofluidic Salivary Exosome Isolation: A Liquid Biopsy Compatible Approach for Human Papillomavirus—Associated Oropharyngeal Cancer Detection,” was published byThe Journal of Molecular Diagnostics.

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