Human papilloma virus (HPV), the culprit behind cervical cancer may hide in small pockets on the surface of tonsils in people not known to carry the virus.
The finding, published in the Journal of the American Medical Association, could be pivotal for the prevention of cancers that form on the tonsils and tongue.
Only about five per cent of HPV-infected people go on to develop cancer of the mouth or throat, suggesting most people’s immune systems can easily hold back HPV infections.
The researchers found Human Papilloma Virus encased in biofilms inside pockets on the tonsil surface, called tonsil crypts, which is where HPV-related head and neck cancers often originate.
They studied tissue samples from 102 patients who had elective tonsillectomies.
A tonsillectomy is a surgical procedure to remove the tonsils.
Five of those samples contained HPV and four contained high risk strains, HPV 16 and 18. In every case, HPV was found in tonsil crypts biofilms.The team believes HPV is shed from the tonsil during an active infection and gets trapped in the biofilm, where it may be protected from immune attack.
In the crypts, the virus likely lays in wait for an opportunity to reinstate infection or invade the tonsil tissue to develop cancer.
The research team now plans to investigate potential screening tools, such as an oral rinse, to detect HPV in the mouth and throat.
The next step would be to develop topical antimicrobials that would disrupt the biofilm and allow the immune system to clear the virus.
By mid-adulthood, most people get exposed to HPV. The same strains that cause cervical cancer (mainly HPV 16 and 18) cause head and neck cancers.
While verified tests exist to detect HPV in people before they develop cervical cancer, the same is not true for HPV-related head and neck cancers, which are expected to outnumber cervical cancer cases by 2020.