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Abstract
- Globally, papillomavirus infections
are very widespread in the general population
worldwide. More than 100 genotypes
of human papillomavirus (HPV)
have been identified; they differ in targeted
tissue and carcinogenic activity.
- This article describes the clinical
manifestations, prevalence and modes
of transmission of human papillomavirus
infections, and the role of HPV
in human cancer. A systematic literature
review was carried out to answer
these questions based on methods
developed by Prescrire.
- The most frequent clinical manifestations
of human papillomavirus infection
are cutaneous and anogenital
growths such as warts,papillomata and
condylomata. The HPV genotypes
linked to skin infections differ from
those infecting the anogenital area.
Genotypes HPV-16 and HPV-18 are frequently
associated with high-grade cervical
dysplasia.
- The frequency of HPV infections
varies widely from one population to
another. HPV (usually genotype 16) is
found in 1.5% to 44% of cervical smears.
In the 1990s, 25% of women between
20 and 29 years of age in the United
States were seropositive for HPV-16.
- Papillomavirus is highly persistent
in the environment, on contaminated
objects, linen, floors. Skin infections can
occur through indirect or direct contact.
Most anogenital infections are sexually
transmitted.
- Most papillomavirus infections are
asymptomatic, latent or transient.
Various factors, especially immunosuppression,
increase the persistence
and severity of infections, and can promote
progression to cancer.
- The DNA of some highly carcinogenic
HPV genotypes (especially HPV-
16 and HPV-18) is present in 95% to
100% of cervical epidermoid
tumours. Malignant transformation
of lesions due to HPV seems to be
facilitated by HPV persistence, a
high HPV viral load in the cervix,
and immunosuppression.
- However, HPV infection rarely
leads to progression to cancer.Only
a minority of infections persist for
several years, and only about 10% of
low-grade lesions progress to a higher
grade. About 5% of high-grade
lesions progress to invasive cancer.
- Other anogenital cancers, such as
cancer of the anus, vulva, vagina and
penis, appear to be linked to HPV (usually
genotype 16).