Human papillomavirus has many different types, some of which cause cancer, while others are less harmful. It affects the skin and mucous membranes. Both adolescent and adult men and women can develop HPV. Because of how HPV acts, it can "block" the body's cells from doing their work to prevent excessive cell growth. Some of these growths can lead to several forms of cancer.
Definition
There are more than 100 types of human papillomavirus, 30-40 of which are sexually transmitted. These include viruses that cause warts transmitted by contact. Some forms of HPV are linked with genital tract tumors, most notably cervical cancer. HPV may also cause abnormal growths in the genital area and cervix. Most HPVs do not cause symptoms. Some HPVs most commonly grow in the moist genital area, and can increase the risk for cervical cancer. (See Definition of Human papillomavirus, Grafs 1, 4)
Link to Cancer
The "high risk" HPV (those caused by sexual contact) types include types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 69 and potentially others. These HPVs are considered to be a major cause of cervical cancer. HPV may also be implicated in cancers of the vagina, anus, vulva, the oropharynx (middle throat, including the soft palate), the base of the tongue and tonsils. In men, HPV has been linked to penile cancer. (See Definition of Human papillomavirus, Grafs 6. 8 and 10)
General Information
The human papillomavirus produces proteins that are designated as E5, E6 and E7. These proteins block the cells from preventing overgrowth. The HPV E6 protein will interfere with the human protein p53, which acts to prevent tumor growth. Some HPV types are categorized as low risk while others fall into the high risk category (the low risk HPVs rarely cause cancer while the high risk HPVs which are more likely to cause cancer are the types classified as high risk. Both HPV types are capable of causing abnormal growths. (See Definition of Human papillomavirus, Grafs 7, 11)
Causes
HPV can cause infection when the virus enters the body through a small cut, a tiny tear in the skin or an abrasion. It is primarily spread by skin-to-skin contact. The HPV associated with genital warts is spread by sexual contact. Those infections causing HPV of the mouth or upper respiratory tract (throat) are contracted via oral sex. It is rare, but a mother with HPV can pass the virus to her child during birth. The resulting infection in the baby can show up in the throat or genitals. (See HPV Infection Causes, Grafs 1, 2, 3)
Risk Factors
The higher the number of sex partners, the greater the risk of contracting HPV. If a person has a sex partner who has had multiple partners, the risk of contracting HPV increases. Another risk factor is the age of the patient when diagnosed with HPV. According to the Mayo Clinic, younger women may be more vulnerable biologically to contracting this virus. The Mayo Clinic says young men are also at increased risk, though the virus isn't diagnosed in them as often. Another risk is a vulnerable immune system. This may be because of HIV/AIDS infection or from taking drugs that deliberately suppress the immune system after an organ transplant. (See Human papillomavirus Infection Risk Factors, Grafs 1, 2, 3)
Treatment and Prevention
Pap smears to detect atypical cervical cells can be done to determine if a woman has contracted HPV. Because HPV can lead to cervical cancer, follow-up testing must be done. There is no similar test for men, but they should be checked annually by their doctor for symptoms of anal or penile cancer.
Using a latex condom can prevent some, but not all, HPV infections. If a wart is not covered by the condom, the partner who comes into contact with this wart is exposed to HPV. Currently, the only HPV vaccine available is Gardasil, and it is available only to teen girls and young women. Microbicides are under development for women to use so they can take an active role in preventing HPV and possible cervical cancer. Results of BufferGel, which is undergoing testing, are expected in 2009.
Tags: cervical cancer, high risk, cancer Definition, cause cancer, Definition Human, Definition Human papillomavirus, Human papillomavirus