Cervical Intraepithelial Neoplasia (CIN)/HPV

Definition
Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia is the potentially premalignant transformation and abnormal growth (dysplasia) of squamous cells on the surface of the cervix.  CIN is not cancer, and is usually curable.  Most cases of CIN remain stable, or are eliminated by the host's immune system without intervention. However a small percentage of cases progress to become cervical cancer, usually cervical squamous cell carcinoma (SCC), if left untreated.

Symptoms
Women who have CIN do not generally have symptoms, as the changes are in the epithelial cells, and do not cause discomfort. The earliest microscopic change corresponding to CIN is dysplasia of the epithelial or surface lining of the cervix, which is essentially undetectable by the woman. Cellular changes associated with HPV infection, such as koilocytes are also commonly seen in CIN. CIN is usually discovered by a screening test, the Papanicolaou or "Pap" smear. The purpose of this test is to detect potentially precancerous changes. An abnormal Pap smear result may lead to a recommendation for colposcopy of the cervix, during which the cervix is examined under magnification. A biopsy is taken of any abnormal appearing areas. Cervical dysplasia can be diagnosed by biopsy.

A group of about 30-40 HPVs is typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted HPVs may cause genital warts. However, other HPV types which may infect the genitals do not cause any noticeable signs of infection.

Causes/Human Papilloma Virus (HPV)
The major cause of CIN is chronic infection of the cervix with the sexually transmitted human papilloma virus (HPV), especially the high-risk HPV type 16 or type 18. Over 100 types of HPV have been identified. About a dozen of these types appear to cause cervical dysplasia and may lead to the development of cervical cancer. Other types cause warts.  Each HPV type is identified by a number (e.g. HPV 16). Some types of the virus can cause genital warts, and other types can cause CIN in the cells of the cervix. CIN usually clears up once the immune system has got rid of the virus. In some women the virus stays for a number of years, and in a few of these women the CIN will develop into cancer if it is not treated.

Papilloma viruses are a diverse group of DNA-based viruses that infect the skin and mucous membranes of humans and a variety of animals. Approximately 130 human papillomavirus (HPV) types have been identified.
Some HPV types can cause warts while others may cause a subclinical infection resulting in precancerous lesions. All HPVs are transmitted by skin-to-skin contact to any substance that adheres to and transmits infectious material. 
 
Risk factors
Some risk factors that have been found to be important in developing CIN are:

• Women who have had multiple sexual partners
• Women who become infected by higher risk types of HPV, such as HPV type 16, 18, 31 or 45.
• Women who smoke
• Women who are immunodeficient
• Women who give birth before age 17

The disease path of this condition has a large number of courses, so it is important that women between the ages of 18 and 35 be especially careful to have regular cervical exams. Between 250,000 and 1 million American women are diagnosed with CIN annually. Women can develop CIN at any age, however, women generally develop it between the ages of 25 to 35.

Progression
It was once thought that cases of CIN progressed through stages I, II, III toward cancer in a linear fashion; but most cases of CIN spontaneously regress. About 50% of CIN II will regress within 2 years without treatment. Progression to cancer typically takes 15 (3 to 40) years. It is important to note, however, that cancer can occur without first detectably progressing through these stages and that a high grade intraepithelial neoplasia can occur without first existing as a lower grade.

It is thought that the higher risk HPV infections, have the ability to inactivate tumor suppressant genes such as the p53 gene and the RB gene, thus allowing the infected cells to grow unchecked and accumulate successive mutations, eventually leading to cancer.  It is important to remember that some of these serotypes only cause warts and most of the oncogenic serotypes do not progress to cancer. However when advanced dysplasia or cancer is present you can be certain that one or more of the HPV oncogenic types is present and has been present and undetected for a long time (years).

When to see a doctor
Cervical screening is a way of detecting early changes in the cervix so that treatment can be given to prevent a cancer developing.  As there are no symptoms that a woman can feel, it is essential that women have regular screening and a cervical Pap smear test. A cervical Pap smear is used to detect cellular abnormalities. This allows targeted surgical removal of condylomatous and/or potentially precancerous lesions prior to the development of invasive cervical cancer.

Although some women put off their cervical screening exams because they are not feeling any discomfort, the prevalence of this disorder, especially among young sexually active women suggests that an annual test should be scheduled. 

Sources:  Wikipedia, Women’s Health

Participate in a Clinical Research Study for Cervical Intraepithelial Neoplasia (CIN)/HPV
If you have been diagnosed with CIN 2 or CIN 3 and you may want to consider participating in a clinical research study. Please click here to complete an on-line application or call:

602-931-4507, ext 225
Compensation may be available to qualified participants for travel in the Phoenix, AZ area, including but not limited to Gilbert, Chandler, Mesa, Scottsdale, Glendale Peoria, and Sun City.
Participation is voluntary.

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