7 days ago
STD suffered by 42million Americans 'actively drives' skin cancer, study suggests
A sexually transmitted disease spread by kissing and oral sex has been linked to skin cancer for the first time.
Human papillomavirus (HPV) is the most common sexually transmitted disease in the US, infecting around 42million Americans at any time and it is already known to cause cancers of the throat, anus and cervix.
But now, researchers at the National Institutes of Health say the virus could also cause squamous cell carcinoma, the second most common skin cancer in the US, with 1.8million cases diagnosed every year.
The team made the link after studying a 34-year-old woman who developed skin cancer on her forehead that kept returning despite surgery and immunotherapy.
Doctors initially suspected the recurrent cancer was due to a rare condition she had called RIDDLE syndrome, which weakens the immune system and makes the body more sensitive to radiation.
But analysis at the NIH revealed HPV had incorporated itself into the genes of her cancer cells, which scientists said had led them to become more aggressive.
Further tests showed that her skin cells could still repair sun damage, suggesting ultraviolet (UV) exposure was not the main driver of her skin cancer.
Dr Andrea Lisco, a virologist who led the study, said: 'This discovery could completely change how we think about the development, and consequently the treatment, of [skin cancer] in people who have a health condition that compromises immune function.
'It suggests that there may be more people out there with aggressive forms of [skin cancer] who have underlying immune defect and could benefit from treatments targeting the immune system.'
The findings, published in the New England Journal of Medicine last week, are still preliminary and only suggest a potential link between HPV and skin cancer.
More research is needed to confirm the findings, and it is not clear at this time what proportion of skin cancer cases may be caused by the virus.
The patient was immunocompromised and unable to produce enough healthy T cells, a key part of the immune system, to fight off the virus.
Doctors treated her with a stem cell transplant to restore her immune system.
Three years later, her skin cancer has not returned, and other HPV-related complications, such as growths on her tongue and skin, have also disappeared.
Researchers said she was infected with beta-HPV, a type of HPV that is present on the skin and can be spread through sexual contact.
The variant differs from alpha-HPV, which is linked to cancer in the throat, anus and cervix.
Researchers found that the virus had embedded itself in the cancer cells' DNA and was driving them to produce viral proteins, triggering mutations that likely fueled the tumors growth.
There are 13million new HPV cases in the US every year, typically attacking the skin and mucous membrane before it is cleared by the immune system.
But in persistent HPV infections, studies suggest that mutations occur in cells that lead to the development of cancer.
The immune system normally clears the infection by itself, with many patients unaware they ever had HPV.
But in some cases the infection can cause symptoms, like warts, with doctors treating these using surgery or prescription creams to destroy the growths.
About 13,000 cases of cervical cancer are diagnosed in women every year, of which 90 percent are estimated to have been caused by HPV infections.
There are also about 7,854 cases of anal cancer every year in the US, with 91 percent of these cases linked to the virus.
And about 13,000 cases of laryngeal cancer are diagnosed in the US annually, of which only around two to three percent are estimated to be caused by HPV.
The number of people infected with HPV is believed to have fallen in recent years amid rising uptake of the vaccine against the virus.
Overall, nearly 60 percent of those aged 13 to 15 years were vaccinated against the disease in 2023, double the around 30 percent a decade earlier.
But the disease still remains the most common STD in the US, and infects millions of people every year.
Cases of squamous cell carcinoma, however, have spiked in recent years and risen by 200 percent in the last three decades, estimates suggest.
This has primarily been linked to more exposure to UV rays from the sun and tanning beds.
Warning signs of the cancer include a firm, raised bump or nodule on the skin, or a scaly, red or pink patch or sore that does not heal.
Those with long-term sun exposure, fair skin, or who are over 65 years old are most likely to be diagnosed with the disease. Men are also twice as likely to be diagnosed as women.
Doctors normally treat the cancer using surgery or chemotherapy, and it has a good survival rate.
More than four in five cases are caught in the early stages, where patients have a five-year survival rate of 99 percent. But if the cancer spreads in the body, this drops to 20 percent.
