Human papillomavirus (HPV) is a highly prevalent sexually transmitted infection, infecting millions of people globally. With more than 200 types known, HPV infections are usually transient and nontrophic. Yet, ongoing infection with high-risk HPV types is an established etiologic factor in the carcinogenesis of many cancers, particularly cervical, anogenital, and oropharyngeal cancer. As such, understanding the mechanisms by which HPV causes cancer and how to prevent it, is vital for reducing the global cancer burden.
Understanding the crucial relationship between HPV and cancer sheds light on the importance of early detection through screening, and the latest treatment advancements. With effective vaccines, improved screening tools, and emerging therapies on the horizon, there are now more opportunities than ever to combat HPV-related cancers. In conversation with Jagran English, Dr. Sravan Kumar, Consultant Medical Oncology and Bone Marrow transplant physician, Manipal hospital Vijayawada, shares insight on taking meaningful steps toward prevention, early intervention and treatment strategies.
HPV Virology And Oncogenesis
HPV is a small double-stranded DNA virus that infects epithelial cells. It comprises early (E) and late (L) genes, of which E6 and E7 are the major oncogenic proteins. These proteins are responsible for malignant transformation by inhibiting tumour suppressor proteins like p53 and retinoblastoma (Rb), which causes unchecked cell growth and genomic instability.
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Dr. Sravan Kumar states, “HPV infection starts when the virus enters basal epithelial cells via microabrasions.” He further adds, “Although most infections clear without harm, oncogenic HPV types can become integrated into the host genome, interfering with normal cellular control and leading to cancer development.”
Cancers Associated With HPV
Cervical Cancer
Cervical cancer is still one of the best-studied HPV-related cancers. Almost all cases are associated with persistent infection with high-risk HPV types, especially HPV 16 and 18. The process of progression from cervical intraepithelial neoplasia (CIN) to invasive carcinoma is slow, which makes regular screening and early treatment very crucial.
Anogenital Cancers
HPV is also responsible for vulvar, vaginal, anal, and penile cancers. Of these, anal cancer has the most virally associated cancer, with HPV 16 identified in most cases. Dr. Sravan Kumar mentions, “ Immunocompromised patients, especially those with HIV, are at much greater risk because of impaired viral clearance.”
Oropharyngeal Cancer
Over the past two decades, HPV has been recognized as a major contributor to oropharyngeal squamous cell carcinoma, particularly in the tonsillar and base of tongue regions. Unlike HPV-negative head and neck cancers, HPV-positive oropharyngeal cancers often occur in younger individuals and have a more favourable prognosis.
Epidemiology And Risk Factors
HPV is also spread by sexual contact, both vaginal, anal, and oral intercourse. Dr. Sravan Kumar shares certain risk factors that promote persistent infection and cancer development, such as:
Early and frequent sexual behaviour and multiple sex partners
Immunosuppression (HIV infection, for example)
Smoking and co-infection with other STIs
Failure to follow routine screening and HPV vaccination
Vaccine Against HPV (Image Credits: Canva)
Prevention And Control
HPV Vaccination
Dr. Sravan Kumar says, “Prophylactic vaccines against HPV, including bivalent, quadrivalent, and nonavalent formulations, have drastically lowered rates of high-risk HPV infection as well as consequent precancerous lesions.” Extensive vaccination programs have found optimal success in the reduction of disease burden across young populations.
Screening And Early Detection
Cervical cancer screening by Pap smears and HPV DNA testing is still the gold standard for early detection and prevention. New screening methods, such as self-sampling for HPV testing, are under investigation to increase accessibility, particularly in resource-poor settings.
Future Directions
Current investigation of therapeutic vaccines and specific treatments for HPV-related cancers is promising for enhanced control. Immunotherapies, such as checkpoint inhibitors, are also being studied actively for their potential in the treatment of advanced-stage HPV-related cancers. Further investigation of viral latency and mechanisms of reactivation can also improve preventive interventions.
HPV is a well-documented oncogenic virus with a profound influence on the incidence of cancer worldwide. Dr. Sravan Kumar shares, “Prevention by vaccination, routine screening, and early detection continues to be paramount in preventing the burden of HPV-associated cancers.” Continued research and clinical advancements will play a crucial role in further diminishing the effects of HPV-associated cancers in the future.
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