1) What Is Human Papillomavirus?
Human papillomavirus, HPV, is a broad, umbrella name for a large group of more than 150 viruses. Each of these viruses within the spectrum of HPV is designated by a number, such as HPV-1, HPV-2, HPV-3, etc….[1,2] Specifically, the “papilloma” part of the name refers to warts that can be caused by several of the virus types.
2) What Does Human Papillomavirus Cause?
Human papillomavirus can cause both non-cancerous and cancerous growths of the affected skin and mucosal surfaces (i.e. the wet parts of the mouth, eyes, nose, etc). While certain HPV strains can cause abnormal growths, HPV also lives on healthy, normal skin without causing any complications. More than a dozen strains of HPV are linked to certain types of cancer such as cervical, vulvar, vaginal, penile, anal, and mouth/throat cancers. The low-risk strains of HPV, such as HPV-1 and HPV-2, can cause warts in places like the feet and the hands. People with compromised immune systems are at higher risk for HPV infections. In some cases, HPV can cause a skin cancer know as squamous cell carcinoma. Squamous cell carcinoma is more likely to occur due to an HPV infection when the individual has a weakened immune system. While squamous cell carcinoma is the most common type of cancer related to HPV infection, other cancers, such as cervical cancer, can develop as well in individuals with a weak immune system.
3) How Does Human Papillomavirus Cause Cancer?
When a cell becomes cancerous, it undergoes changes that alter its life cycle. In the high-risk types of the human papillomavirus, the virus leads to the production of certain proteins (namely E6 and E7). These proteins can lead to a cancerous transformation in the cells they infect by making those cells immortal. While these two specific proteins of E6 and E7 are often not enough to cause the cell to undergo the complete cancerous transformation, they prolong the lifespan of the cell, allowing it to accumulate more mutations and defects, eventually leading to the possibility of cancer.[6,7] For example, in normal cells, DNA damage is common and is often repaired or the cell self-destructs. However, the human papillomavirus proteins can impair normal DNA repair and prevent the death of abnormal cells that can then live on to become cancerous.
4) How Is Human Papillomavirus Spread?
HPV spreads through direct physical contact. The HPV virus can infect epithelial cells, which are cells covering surfaces of the body, such as the mouth and the skin. Not surprisingly, this is where most warts and other growths can occur. Areas with a damp, moist environment, such as a community center shower or swimming pool can also be areas for potential transmission.
Intimate contact between body surfaces, such as sexual intercourse as well as kissing, can spread the virus more easily. Even if you have not had sexual intercourse, you can be at risk for human papillomavirus infection because the virus can spread through genital-to-hand contact as well as hand-to-hand contact. Nail biting and shaving can spread warts, leading to a persistent infection. Mothers can spread human papillomavirus to babies during delivery as well. Due to the ease of transmission, human papillomavirus is the most common sexually transmitted infection (STI).[10,11] According to the Centers for Disease Control and Prevention, more than 80% of sexually active men and women acquire HPV by the age of 45.
5) What Does Negative Testing Mean?
I had a Pap smear, and the doctor tested for human papillomavirus. It came back negative. Does that mean I am negative for the virus just down there, or throughout my whole body?
Where warts/growths occur depends on the specific strain of HPV, and most infections are within a local area of the surface cells. Most patients can be infected with multiple different types of human papillomavirus. For example, the HPV strains 16, 18, 31, 33, 45, and 59 are most commonly associated with squamous cell carcinoma and cervical cancer. In contrast, HPV types 1, 2, 4, 27, 29, and 57 are most commonly associated with non-cancerous warts on the hands and feet. Your Pap smear may indicate that you are negative for the “high-risk” human papillomavirus strains generally associated with cervical and squamous cell carcinoma, but you may still be positive for other strains of human papillomavirus that are considered low-risk.
6) What Can I Do?
One potential prevention option is a human papillomavirus vaccine. The Centers for Disease Control and Prevention recommend all children around age 11 or 12 be vaccinated twice against HPV, spaced between six to twelve months. Cervical screening through your gynecologist in combination with HPV vaccination can protect against a higher prevalence of cancer. Annual consultations with your dermatologist can assuage any fears of skin cancer or unwelcome warts.
Frequent hand washing, especially after contact with either hands or genitals may help prevent the spread of HPV. Additionally, when in communal showers and swimming pools, wearing shoes may help reduce the chance of infection.