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HPV 68 - genital human papillomavirus
Medical expert of the article
Last reviewed: 06.07.2025
Among the currently known strains of DNA-genomic human papillomavirus (HPV), the most studied is the alphapapillomavirus genus. This genus includes viruses of high oncogenic risk. Some experts include HPV 68 among them, although they consider it a rare type.
Structure HPV type 68
The structure of HPV 68 is virtually identical to that of other papillomaviruses. HPV type 68 forms an icosahedral capsid (protein shell) with a diameter of 50 nm. The capsid consists of 72 pentamers of the structural protein L1 linked to each other by disulfide bonds. This binding mediates conformational changes in the viral capsid, which ensures the initial attachment of the virion to the host cell and facilitates infection. [ 1 ]
The double-stranded circular DNA of HPV 68 has a region that encodes the early proteins E1-E7 and a region L that encodes the late structural proteins of the viral envelope (L1 and L2).
The life cycle of the virus consists of several stages. At the initial stage, the virus must attach to the cell and penetrate through its membrane inside – by endocytosis. Then the viral DNA is released into the nucleus of the host cell, integrating into its genome. After this, the virion is assembled inside the nucleus of the affected cell – with the encapsulation of the genomic DNA by the L2 protein.
The leading role in the replication of the viral genome is played by the viral proteins E6 and E7, which are considered oncogenic. They not only use the mechanism of cellular DNA replication to introduce their own DNA into cells, but also neutralize the cellular protein p53, a tumor suppressor. In addition, the E7 protein, interacting with the transmembrane protein TMEM173, which induces the production of type I interferon, suppresses innate immunity. [ 2 ]
In this way, HPV protects itself from the host's defense mechanisms at the extra- and intracellular levels. And with high activity of the immune system, the virus can wait out unfavorable conditions for itself, being in a latent form.
Read also – Human papillomavirus: structure, life cycle, how it is transmitted, prevention
On the issue of oncogenicity of HPV type 68
Many types of the human papillomavirus of the Alphapapillomavirus genus are characterized by a high risk of developing cancer. The number of such types varies from 13 to 19, and only 11 of them have proven oncogenicity. These are HPV 16, 18, 31, 33, 35, 45, 39, 51, 52, 56, 58.
They primarily infect the mucous membrane of the anogenital area, oral cavity and oropharynx. The most common of them are: HPV 16, 18, 45, 31, 33, 35, 52 and 58.
The degree of carcinogenicity of these types varies. It is very high for HPV 16 and slightly lower for HPV 18, which causes about 72% of cases of cancer development associated with papillomatous infection.
Almost 18% of cervical cancer cases involve viruses of the A9 group (HPV 31, 33, 35, 52, 58) and A7 (HPV 45 and 59). And the share of HPV 68, HPV 66, HPV 26, HPV 53, HPV 70, HPV 73 and HPV 82 – as an etiologic factor of oncogenesis and single HPV infections in invasive cervical cancer – together accounts for 0.9-1.7%. According to some studies, in 55.3% of cases, genotypes of viruses of the A7 or A9 groups are detected as coinfections.
Without sufficient clinical and epidemiological data to prove the oncogenicity of HPV 68, the WHO International Agency for Research on Cancer (IARC) currently classifies this type of papillomavirus as probably carcinogenic.
According to the latest data from the US National Cancer Institute (NCI), HPV is the main cause of approximately 5% of all cancer cases worldwide.
Symptoms
Cervical neoplasia is considered to be the result of persistent human papillomavirus infection. However, HPV 68 itself is less likely than others to be involved in malignant tumors of the cervix uteri.
Experts believe that HPV 68 in women can cause cervical dysplasia, which is accompanied by symptoms such as discomfort, as well as itching, burning or pain in the genital and suprapubic area; unusual vaginal discharge.
Read more in the publications:
Problems associated with the human papilloma virus also concern men, since the main way of transmission of the virus is sexual. And HPV type 68 in men can cause the development of penile cancer, anal cancer, tumors of the oropharynx and larynx.
What symptoms may occur, detailed in the publications:
Diagnostics
How to diagnose human papillomavirus, in detail in the articles:
- Papillomavirus infection: detection of human papillomavirus
- Human papillomavirus tests
- Diagnosis of cervical dysplasia
As for the methods of quantitative determination of total high-risk HPV, real-time PCR (Hybrid Capture II test) is used. This analysis helps in the diagnosis of sexually transmitted HPV infection and provides high-quality molecular detection of 13 different types of high-risk HPV (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68 - without differentiation of the individual type of the virus (i.e. genotyping). Therefore, there is no such thing as the norm of HPV type 68, and the test result establishes the viral load - the number of copies of genomic DNA (Lg) per cell equivalent (log10 viral copies / 1 ng of cellular DNA). If the indicator in the analysis decoding does not exceed 3 Lg, then the concentration of HPV is considered clinically insignificant. [ 3 ]
We do not yet have a HPV HCR genotype-titer PCR kit (R-V67-F-CE) available for detection, differentiation and quantification of 14 HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68). Here, each HPV type is recorded separately, which makes it possible to differentiate the virus genotype and determine its quantity. [ 4 ]
Prevention HPV type 68
To prevent infection with the human papilloma virus, doctors recommend:
- orderly sex and protected sexual intercourse;
- women should undergo preventive examinations by a gynecologist, men should consult a doctor if they experience any alarming symptoms in the anogenital area;
- strengthen the immune system.