Human papillomavirus (HPV) infection with high-risk types has been shown to be a necessary factor in the development of cervical cancer.HPV DNA may be detected in virtually all cases of cervical cancer.Not all of the causes of cervical cancer are known. Several other contributing factors have been implicated.
Human papillomavirus infection
In the United States each year there are more than 6.2 million new HPV infections in both men and women, according to the CDC, of which 10 percent will go on to develop persistent dysplasia or cervical cancer. That is why HPV is known as the "common cold" of the sexually transmitted infection world. It is very common and affects roughly 80 percent of all sexually active people, whether they have symptoms or not. The most important risk factor in the development of cervical cancer is infection with a high-risk strain of human papillomavirus. The virus cancer link works by triggering alterations in the cells of the cervix, which can lead to the development of cervical intraepithelial neoplasia, which can lead to cancer.
Women who have many sexual partners (or who have sex with men who had many other partners) have a greater risk.
More than 150 types of HPV are acknowledged to exist (some sources indicate more than 200 subtypes). Of these, 15 are classified as high-risk types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82), 3 as probable high-risk (26, 53, and 66), and 12 as low-risk (6, 11, 40, 42, 43, 44, 54, 61, 70, 72, 81, and CP6108). Types 16 and 18 are generally acknowledged to cause about 70% of cervical cancer cases. Together with type 31, they are the prime risk factors for cervical cancer.
Genital warts are caused by various strains of HPV which are usually not related to cervical cancer. However, it is possible to have multiple strains at the same time, including those that can cause cervical cancer along with those that cause warts. The medically accepted paradigm, officially endorsed by the American Cancer Society and other organizations, is that a patient must have been infected with HPV to develop cervical cancer, and is hence viewed as a sexually transmitted disease, but most women infected with high risk HPV will not develop cervical cancer.
Use of condoms reduces, but does not always prevent transmission. Likewise, HPV can be transmitted by skin-to-skin-contact with infected areas. In males, there is no commercially available test for HPV, although HPV is thought to grow preferentially in the epithelium of the glans penis, and cleaning of this area may be preventative.
Cofactors
The American Cancer Society provides the following list of risk factors for cervical cancer: human papillomavirus (HPV) infection, smoking, HIV infection, chlamydia infection, stress and stress-related disorders, dietary factors, hormonal contraception, multiple pregnancies, exposure to the hormonal drug diethylstilbestrol, and family history of cervical cancer. Early age at first intercourse and first pregancy are also considered risk factors, magnified by early use of oral contraceptives. There is a possible genetic risk associated with HLA-B7.[citation needed]
There has not been any definitive evidence to support the claim that circumcision of the male partner reduces the risk of cervical cancer, although some researchers say there is compelling epidemiological evidence that men who have been circumcised are less likely to be infected with HPV. However, in men with low-risk sexual behaviour and monogamous female partners, circumcision makes no difference to the risk of cervical cancer
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