Almost all of the cervical cancers are caused by human papilloma virus (HPV). In fact, HPV 16 and 18 are known to cause around 70% of all the cervical cancer cases worldwide. Therefore, an understanding of HPV and how they cause cervical cancer is important, if we are serious about reducing the occurrence of cervical cancer, which is the cancer of the cervix.
Human Papilloma Viruses
Human papilloma viruses are a part of a group that contains more than 150 viruses. Some of these 150 viruses are known for causing genital warts, while others are known for causing genital infections. Some of the HPVs are also known for causing cervical, oral, and genital cancers. The HPVs that cause cancers are known as high risk viruses.
High Risk HPVs
One of the main things that we have to understand about HPVs is that not all of them are high risk for cervical cancer. HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, and 69 are the ones that we need to be concerned about, because they are the ones which are associated with cancer risk.
HPV Infection Quite Common
The second main point that we need to understand about HPV infections is that they are quite prevalent. Studies have indicated that at least 42% of the women are infected with a HPV at one point or another in their lifetime. Moreover, almost 50% of the people who are active sexually will get the infection at one point or another in their lifetime. In most of the cases, body’s immunity is able to successfully deal with the infection. The infection usually goes away in one to two years. However, in some cases the infection lingers on and can lead to cervical cancer.
The important point to understand here is that not all HPV infections lead to cervical cancer. Even infections caused by high risk HPV 16 and HPV 18 do not always lead to cervical cancer. Moreover, doctors point out that it will take around ten to twenty years for a HPV infection to develop into cervical cancer.
How HPV Infection Leads to Cervical Cancer
The HPV genital infections are transmitted from one person to another via skin contact during sex. In fact, sexual intercourse does not have to take place in order for the infection to be transmitted from one person to another. Only skin to skin contact with the infected part is required for the infection to be transmitted.
The HPV infection starts by infecting the epithelial cells. These cells make up the inside and outer covering of many of the body parts like, throat, anus, vagina tract, penile tract, and skin. As soon as a high risk HPV has infected an epithelial cell, the virus starts producing proteins.
In the human body, the division of the cells is controlled by two proteins, identified as p53 and RB. In high-risk HPVs, researchers discovered two genes, referred to as E6 and E7. These two genes produce certain proteins, which can attach to the p53 and RB proteins in the human body.
Once the HPV proteins attach to the p53 and RB proteins, they start to hinder proper functioning of p53 and RB proteins. In other words, proteins produced by high risk HPVs begin to hinder proper cell division in the infected epithelial cells, which then begin to grow uncontrollably. After some time, the infected epithelial cells undergo permanent genetic change. Such epithelial cells then can become cancerous cells in the future. However, this might take ten to twenty years.
In the initial stage, the infected epithelial cells become shapeless or distorted. These abnormal epithelial cells will gradually overtake the normal epithelial cells present in the cervix’s surface. Cervical lesions will begin to appear. Then over a period of time, this will lead to carcinoma in situ.
If carcinoma in situ is left undiagnosed or untreated, the precancerous epithelial cells will then begin to invade the muscles and tissues deep inside the cervix. If this happens, it means that the infected epithelial cells have turned cancerous and the concerned person has cervical cancer.
Infection Stays Dormant
One of the main problems with HPV infections is that they show no symptoms. In most cases, the body’s immunity is able to successfully deal with HPV infections; however, it does not mean that the infection has totally gone away. The virus can lie dormant for many years before striking again. It is thus important for sexually active people to go for regular tests to detect HPV infections.
DNA and RNA Tests for HPV Detection
Today there are tests available that can find out whether DNA or RNA of some high risk HPVs is present in the cervix or not. Some tests can find out whether DNA is present or not, but cannot determine to which type of HPV the DNA belongs to. Some tests can find the RNA of several high risk HPVs.
Scientists have also developed a test that can find out whether the DNA for HPV 16 and 18 is present in the cervix or not. The good news is that all of these tests are able to detect the infection before it is able to cause any defects in the epithelial cells. As per the FDA guidelines, doctors can do these tests on women whose Pap tests have shown cell abnormalities. Women above the age of 30 can also go for these cervical screening tests along with the regular Pap test.
Need for Regular Pap Test
Sexually active women should go for Pap tests on a regular basis. Though a Pap test is not able to detect HPV infection, it is able to detect cell abnormality in the cervical area.
As mentioned above, it takes anywhere between ten to twenty years for a high risk HPV infection to develop into cervical cancer. Thus if you go for regular Pap tests, doctors will be able to detect and treat cell abnormalities on time.
At present HPV infections cannot be treated; however, precancerous lesions present in the cervix can be treated. Doctors can opt for cryosurgery in order to treat the precancerous lesion. Cryosurgery involves freezing the affected area in order to destroy the precancerous cells.
Loop electrosurgical excision procedure (LEEP) is another treatment option for precancerous lesions in the cervix. In this procedure, a wire loop is first heated up and then it is used for removing the infected tissues in the cervix.
Laser vaporization conization is another treatment option for precancerous lesions. In this procedure, laser is used for eliminating the infected cervical tissues. Doctors also use surgical conization to remove the abnormal cervical tissues. During this surgery, the doctor might use a laser or scalpel or both to remove the abnormal tissues in the cervix.
Scientific studies have proven beyond doubt that there is a clear link between HPVs and cervical cancer. HPV infection is common to all types of cervical cancers. Regular Pap tests and DNA or RNA tests are the most effective ways of reducing the occurrence of cervical cancer. In the past decades or so, USA has seen a drastic decline in cervical cancer cases. This has been made possible only because women in US go for regular Pap tests and DNA or RNA tests. Therefore, if you are serious about cervical cancer, you need to spread the word about Pap tests.