How a virus might protect against skin cancer

Previously, scientists have linked the presence of human papillomavirus to an increased risk of certain cancers. In a surprising twist, the latest research finds that the virus might help defend against skin cancer.

The role of HPV in skin cancer

• The authors of the recent study were particularly interested in cutaneous squamous cell carcinoma (SCC), stating that it is the second most common type of cancer.
• Ultraviolet (UV) light from the sun is the primary preventable cause of skin cancer, but from 1992 to 2012, the incidence of skin cancer in the United States doubled. Scientists are trying to uncover additional ways of lowering the risk of skin cancer.
• Some scientists have theorized that HPV plays a role in SCC. This idea is based on earlier research showing that a genus of HPV called beta-HPV is present in the majority of skin cancers among people who have received an organ transplant.
• Individuals belonging to this population have a weakened immune system and are, therefore, more susceptible to cancers that are linked to viral infections. To date, though, scientists have not identified how beta-HPV might increase skin cancer risk.
• According to lead author Dr. Shawn Demehri, "This is the first evidence that commensal viruses could have beneficial health effects both in experimental models and also in humans."
• Looking to the future

These findings open interesting new avenues that might lead to new ways of reducing the risk of SCC. The authors write:

What the scientists found turned the theory of beta-HPV's role in skin cancer on its head.

HPV, immunity, and cancer

The researchers found that the body's immune response to beta-HPV is key. In their experiments, mice that demonstrated an immune response to HPV seemed to have protection from the development of SCC following carcinogenic UV or chemical exposure.

Similarly, when the researchers transplanted T cells from those mice into immunocompromised mice, the recipients also developed protection against skin cancer.

In short, it is not beta-HPV that encourages SCC in immunocompromised individuals. Instead, it is the loss of immune function that increases the risk of SCC.