The main factor in the development of squamous cell skin cancer is considered ultraviolet radiation, which can cause genetic mutations in cells. American oncologists have described for the first time a clinical case in which the human papillomavirus contributed to the development of this form of skin cancer.

A study by the US National Institutes of Health has shown that one of the types of human papillomavirus, the β-virus, can cause squamous cell skin cancer if the patient's immune cells do not work properly.

In an article for The New England Journal of Medicine, the aforesaid oncologists spoke about a 34-year-old woman who went to the clinic for examination and treatment of a recurrent case of squamous cell skin cancer. She underwent several surgeries and a course of immunotherapy to destroy the tumor, but it reappeared again and again. At first, doctors thought it was due to a hereditary disorder of the patient’s immune T-cell function, which had made the woman vulnerable to ultraviolet radiation.

But it took a complex genetic analysis before it became clear that it was a rare mutation in the ZAP70 protein, which is necessary for the normal functioning of T-cells, reports Naked Science. And because of this, the immune system was unable to destroy the papillomavirus β-virus, which had penetrated the DNA, where it had begun to multiply, and this had stimulated the growth of the tumor.

The patient needed a stem cell transplant to replace her damaged T-cells with healthy ones. The surgery was successful, and the patient has been free of recurrent aggressive squamous cell skin cancer for more than three years now. This confirms that the hereditary disorder had prevented her T-cells from destroying the beta virus, which directly had caused the skin cancer.

According to the authors of the study, this clinical case suggests that other people with defective T-cells may also be directly susceptible to cancer caused by the β-virus. Previously, it was believed that the β-virus of human papillomavirus, unlike its other forms, cannot integrate into DNA, thus contributing to the development of skin tumors.

The human papillomavirus group includes 27 species of five genera and more than 170 strains. Most sexually active women and men are infected with various types of HPV during their lives. Infection is possible through everyday contact, for example, by shaking hands. The virus enters the human body through scratches and abrasions on the skin.