Mexico City. The high-risk papilloma virus type 16 is the cause of more than 90 percent of cancers of the oropharynx, with an origin, in nine out of 10 cases, in the practice of oral sex, indicated Patricio Gariglio Vidal, from the Department of Genetics and Molecular Biology of the Center for Research and Advanced Studies (Cinvestav), of the National Polytechnic Institute.
Tumors in this area are a subgroup of squamous cell cancer of the head and neck, which have recently increased in frequency (around 878,000 new cases in 2020 worldwide), even more than anogenital. The high-risk papillomavirus is in approximately 25 percent of the cases present in the world, revealed Gariglio.
In his article, published by Cinvestav, he pointed out that the human papillomavirus has double-stranded DNA with a predilection for the squamocolumnar junction of the epithelium. Therefore, the tonsils, soft palate, and base of the tongue act as hosts, providing access to their basal layer for viral reproduction.
The cancers of the oropharynx, explained the specialist, include diseases of the mentioned tissues and the surrounding ones. “Although exposure to tobacco and alcohol are risk factors, past decades have seen an increase in those related to high-risk human papillomavirus, particularly type 16. The increased incidence of cases linked to This virus makes this disease the most common malignant neoplasm in the United States, where there is an excellent record of patients and deaths from different types of cancer. In fact, in that country, 60 percent of squamous cell cancers of the head and neck are of the oropharynx.”
The scientist said that similar trends are observed in northern Europe, where cases associated with high-risk papillomavirus are increasing rapidly (31 percent of squamous cell cancers of the head and neck). In both Central and South America, they have also increased in recent years.
More relevant data
Another relevant fact, argued the expert in molecular biomedicine and oncogenes, is that patients with type 16 positive oropharyngeal cancers have an earlier sexual onset and a greater number of partners with whom they practice oral and vaginal sex during their lives, in relation to those of another origin. In general, “patients are of higher socioeconomic status and less likely to have a history of tobacco or alcohol abuse; although tumors that are associated with high-risk viruses have a better prognosis and response to treatment than those that are negative”.
Gariglio Vidal shared that the therapy for squamous cell cancer of the head and neck is varied. In general “it consists of surgery, when possible, followed by chemotherapy plus radiotherapy. Monoclonal antibodies against the epithelial growth factor receptor are used in combination with radiotherapy in those cancers negative for human papillomavirus, when chemotherapy is not recommended for the patient because it is very toxic. Inhibitors of immune system blockers are also used at checkpoints.”
He added that “retinoids induce differentiation and apoptosis in tumor cells; show antiproliferative and antioxidant activity, presenting great potential as preventive or therapeutic agents. Among the most promising natural compounds in the prevention of squamous cell cancer of the head and neck are retinoids. Vitamin A and its most important metabolite, retinoic acid, have been used in many studies related to therapy for this disease. There are many examples that indicate that retinoids and epigenetic therapy will be among the best alternatives to control this fearsome disease.”
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