02.24.16 last updated.
Over the past decade, David Wong of UCLA and his colleagues have been developing a method for detecting circulating tumor DNA in bodily fluids such as blood and saliva. The approach, known as a liquid biopsy, holds the promise of quicker, less invasive identification of cancers and easier tracking of disease status during the course of treatment.
In a news briefing at the 2016 annual meeting of the American Association for the Advancement of Science (AAAS), Wong described a prototype device — called electric field-induced release and measurement (EFIRM) — that can detect biomarkers in saliva for a malignancy called non-small cell lung cancer (Wei et al., 2014). The device has high accuracy compared to current sequencing technology and is entering clinical testing in lung cancer patients in Asia this year.
The test requires just one drop of saliva and can be completed in 10 minutes in a physician’s office. Dr. Wong envisions using it in conjunction with other diagnostic tools. If a lung X-ray were to show a suspicious nodule, for example, a doctor could do the saliva-based test to help quickly determine whether a cancer is likely.
The test can reliably find genetic mutations involving epidermal growth factor receptor (EGFR), a protein on the surface of cells. It normally helps the cells grow and divide, but some cells in non-small cell lung cancer have too much EGFR, which makes them grow faster. Several drugs can block the growth signal from EGFR, and their use could be ordered promptly by a clinician.
Saliva-based tests might someday allow screening for a variety of cancers in a doctor’s office or laboratory, says Wong, director of UCLA’s Center for Oral/Head and Neck Oncology Research. He and his colleagues have also been exploring the use of saliva-based liquid biopsy technology to detect mutations linked to cancers of the mouth and the back of the throat (called oropharyngeal cancers). Dr. Wong’s work with the ERC consortium explores the use of liquid biopsy of extracellular RNA to detect gastric cancer.