HPV – What Is Human Papillomavirus, and How Does It Cause Cancer?

We know that smoking, obesity, alcohol and heavy processed-meat consumption can cause cancer. However, the contribution of microorganisms to cancer is still insufficiently understood by the public and scientific community. Worldwide, approximately 14 million new cancers are diagnosed annually, and %16are associated with infectious agents , most of which are viruses.

Note: To clarify cancer–microorganism relationships, metagenomic studies are used. Metagenomicsis, in samples such as biopsy tissues, analysis of microorganisms’ genetic material.

• Of all cancers, %5are thought to be caused by HPV. Cervical cancer samples show %99.7HPV detection.
• Apart from the cervix, HPV is also associated with head and neck, vaginal, vulvar, penile, anal and rectal cancers.
• HPV is one of the most common sexually transmitted agents; of the population, %80–90encounter at least one HPV type during their lifetime.
• Of HPV infections, %70–90cause no symptoms; most 1–2 years later clear spontaneously or cause only warts.
• Of the known ~200 HPV types, ~40infect the genital region; among these, 15are, for cervical cancer, high-risk.

In the 1970s, Harald zur Hausen, “HPV may be the cause of cervical cancer” was the hypothesis he proposed. He suggested HPV DNAcould integrate into cervical cells’ DNA. After many years of research, in 1983 he demonstrated HPV DNA in cervical cancer biopsies and proved that HPV-16/18 types were the predominant agents (in ~%70of cervical biopsies).

This discovery paved the way for vaccines against high-risk HPV-16/18 types, providing protection up to %95 . The preventive HPV vaccine received FDA approval in 2006 , and cervical cancer incidence fell significantly in countries administering it routinely.

Viruses published a study (August 2017) suggesting that some enzymes produced against viruses (such as APOBEC3) in our own DNA may also cause cancer-related mutations . This offers a possible explanation for why HPV infection can progress to cancer years later.

There are currently 3 types of HPV vaccine: 2-type (bivalent), 4-type (quadrivalent) and 9-type (nonavalent) HPV vaccines.

In our country, Gardasil (4-type) and Cervarix (2-type) are available. Gardasil 9 in 2014 received FDA approval.

• Girls/ Women: Ages 9–26 · Males: Ages 9–21 are recommended.
• The ideal vaccination age for both sexes is 11–12; your doctor may recommend it from age 9.
• The first sexual contact, before vaccination provides the highest protection; before exposure, against the 4 common types, %100nearly this level of protection is possible.

Conclusion: Infectious agents account for a significant portion of the cancer burden. However, public awareness is low. Furthermore, some infections are vaccine-preventable (HPV, Hepatitis B) or treatable (for example, Helicobacter pylori). Compared with other potential risks frequently discussed in daily life, focusing on infection-related cancers is supported by a higher level of scientific evidence as a prevention strategy.