HPV testing helped
Saliva analysis helped to identify asymptomatic cancer
Sofia Jabotinskaya, Naked Science
A non-invasive test developed by scientists from the Queensland University of Technology was able to detect the DNA of the cancer-associated type of human papillomavirus (HPV-16) in a saliva sample. Persistent infection caused by this virus is considered the main cause of cancer of the oropharynx (tonsils and the area of the base of the tongue). An article about this was published in Frontiers in Oncology (Tang et al., An Occult HPV-Driven Oropharyngeal Squamous Cell Carcinoma Discovered Through a Saliva Test).
The authors of the test, Professor Chamindi Punyadira and Dr. Kai Tan, were able to detect cancer in a person at a very early stage — before any symptoms appeared. The discovery was made during a study of the prevalence of human papillomavirus, which involved 665 healthy people.
In the left amygdala of one of the participants, during a detailed examination initiated due to sustained positive salivary tests, a squamous cell carcinoma measuring only two millimeters was found. At this stage, it was enough to simply remove the amygdala and further observe the condition of the pharynx and larynx. As a rule, cancer of this area is detected only in the late stages, when patients require complex and very effective treatment; because of this, the lethality of such cancer is very high.
According to researchers, in the United States, throat cancer caused by HPV has already surpassed cervical cancer and has become the most common type of cancer caused by HPV. At the same time, unlike cervical cancer, there has not yet been a screening test for this type of oropharyngeal cancer.
A: changes in the viral load in the patient's saliva over time; B: as a result of surgical intervention, a tumor was removed from the left amygdala in this patient; C and D: micrographs of the tumor preparation, stained in different ways. Figure from the article by Tang et al.
"To pass the test, all a person needs to do is give a salivary solution to rinse the mouth. When the test shows HPV type 16 DNA, it is repeated, and if the presence of HPV-16 persists for a certain period of time, we will suspect that there may be a cancerous focus," says Professor Punyadira.
For example, in the patient discussed above, traces of HPV-16 DNA were consistently detected for 36 months, and the number of detected particles consistently increased in tests done after the first test at six, 12 and 36 months. At the same time, after the operation, no signs of viral DNA were found in the patient's saliva.
The authors note that this was the first case in history of a histologically confirmed diagnosis of asymptomatic latent throat cancer diagnosed using a saliva screening test, and that broader validation studies are needed to confirm their group's conclusions. If it turns out that such a test is consistently able to detect HPV-associated cancer in the early stages, the procedure can become a very simple and effective system for detecting a critical marker.
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