Introduction to Skin Cancer
Skin cancer is caused by DNA damage in skin cells. The most common source of that damage is ultraviolet radiation from the sun. However, a new case report published in the New England Journal of Medicine suggests that a type of human papillomavirus (HPV) can also play a role in the development of skin cancer.
The Role of HPV in Skin Cancer
The culprit is a type of human papillomavirus (HPV) that’s regularly found on the skin. It’s long been thought to play a role in the development of skin cancer, but wasn’t believed to be a direct cause. HPV can help UV-damaged DNA build up in cells and turn cancerous. However, in the new case report, doctors found that the virus itself could cause cancerous lesions to form.
The Discovery
The discovery was made in a 34-year-old woman with a weakened immune system; experts said it’s highly unlikely that HPV could play the same role in causing skin cancer in a person with a healthy immune system. “The virus replicated in a somewhat uncontrolled manner and ended up integrating into the skin cells and once they did that, they became cancerous,” said Dr. Andrea Lisco, section chief of the mucosal and cutaneous viral immunopathogenesis unit at the National Institute of Allergy and Infectious Diseases, part of the NIH.
The Case Report
The woman had 43 spots of cutaneous squamous cell carcinoma — the second-most common type of skin cancer, after melanoma —on her face, hands and legs. She had surgery to remove the cancers and immunotherapy, but the cancer returned. When Lisco and his team biopsied several of her new tumors, they found that the woman’s skin cancer was being driven by something they hadn’t seen before: a group of HPVs called beta HPV.
Beta HPV and Skin Cancer
About 90% of people carry a strain of beta HPV. Usually, the virus lives on the skin and doesn’t integrate into the DNA of skin cells. “We shake hands and we pick up those viruses, but if our immune systems are under control, we are fine,” Lisco said. It’s a different group of HPV strains — alpha HPVs — that are linked to a range of cancers. Alpha HPVs live on mucus membranes and can integrate into DNA, causing cancers of the cervix, anus, head and neck.
The Immune System and Beta HPV
The woman in the case report had a genetic condition that weakened her T-cells (a type of immune cell), leaving her immunocompromised. This allowed the beta HPV living on her skin to behave more like alpha HPV, integrating their DNA into her skin cells and replicating undisturbed, turning the cells cancerous. “You don’t know how much you can directly apply the information from one patient to the wide variety of patients,” said Dr. Anthony Oro, professor of dermatology at Stanford Medicine, who wasn’t involved in the case.
Implications and Future Research
However, “it suggests that, in the event that the T-cell arm of the immune system is not doing its job, beta-type HPV viruses could contribute to skin cancer, and maybe other kinds of cancers as well,” he said. The patient needed a stem cell transplant, which replaced her defective T-cells with T-cells that could prevent the HPV from replicating. “We needed to give this patient a whole new immune system,” Lisco said. It worked. Three years post-transplant, the woman’s skin cancer has not returned.
Prevention and Protection
Doctors have known for a long time that some beta HPVs cause changes on the skin, such as warts on the hands and feet. “HPV can integrate and cause changes in the cell cycle, especially in people with suppressed immune systems,” Rossi said. “What was novel about this is that they found out it was a beta HPV that integrated into the DNA.” Other researchers have speculated this was a possibility based on studies in mice, but the new report shows that it can occur in humans. How many people could be at risk is still unknown.
Conclusion
The discovery of beta HPV as a potential cause of skin cancer in immunocompromised individuals highlights the importance of continued research into the relationship between HPV and skin cancer. While the Gardasil HPV vaccine protects against nine strains of alpha HPV, it is unclear how much cross-protection, if any, the vaccine provides against other strains of HPV, including beta HPV. Further studies are needed to fully understand the role of beta HPV in skin cancer and to develop effective prevention and treatment strategies.
FAQs
Q: What is the most common cause of skin cancer?
A: The most common cause of skin cancer is ultraviolet radiation from the sun.
Q: Can HPV cause skin cancer?
A: Yes, a type of human papillomavirus (HPV) called beta HPV can cause skin cancer in immunocompromised individuals.
Q: How common is beta HPV?
A: About 90% of people carry a strain of beta HPV.
Q: Can the Gardasil HPV vaccine protect against beta HPV?
A: It is unclear how much cross-protection, if any, the Gardasil HPV vaccine provides against beta HPV.
Q: What can individuals do to protect themselves from skin cancer?
A: Individuals can protect themselves from skin cancer by wearing sunscreen, covering up their skin from the sun, and getting regular check-ups if they have a weakened immune system.
