How Squamous Cells Can Be Potentially Affected by HPV

Squamous cells are a type of flat epithelial cell found throughout the body, including in the mouth, on the lips, and on the cervix. They are also seen in the middle layers of the skin. Squamous cell carcinoma is a type of cancer that affects the squamous layers of the epithelium. It's the most common cancer of the oral cavity. and also is common in the cervix and the skin.

Gynecologist exam
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Squamous cells often are involved in abnormal Pap smears, as in a diagnosis of ASCUS (Atypical Squamous Cells of Undetermined Significance),which indicates the presences of unusual cells that are not clearly benign or bad.

Potentially pre-cancerous, abnormal Pap smear results are sometimes diagnosed as squamous intraepithelial lesions. This a very specific diagnosis of an abnormal Pap smear.

When you receive this diagnosis, it means that the squamous cells found in the cervix have taken on an abnormal morphology, or shape but aren't necessarily cancerous. In fact, low-grade squamous intraepithelial lesions (LSIL) often heal themselves without intervention.

These lesions are also sometimes known as cervical dysplasias or cervical intraepithelial neoplasia (CIN), High-grade squamous epithelial lesions (HSIL) are more likely to become cervical cancer than LSIL. However, they can also regress.

There are several other Pap smear diagnoses. These include ASC-H, atypical squamous cells, cannot exclude HSIL. As with ASCUS, the meaning of ASC-H is unclear. However, cells diagnosed as ASC-H are more likely to be problematic than those diagnosed as ASCUS.

There is also a Pap smear diagnosis of atypical glandular cells (AGC). This diagnosis refers to changes in the glandular cells in the cervix, which are not part of the squamous epithelium. Changes in the glandular cells generally require more intensive treatment than changes in squamous cells.

Squamous Cells, Cervical Cancer, and HPV

Most cervical cancers and pre-cancers are caused by infections with human papillomavirus (HPV). HPV infects and transforms the squamous cells of the cervix. It can also infect and transform the cells of other tissues in the body.

The 2020 cervical cancer screening guidelines from the American Cancer Society (ACS) recommend people with a cervix get HPV primary testing rather than a Pap test every five years, starting at age 25 and continuing through 65. More frequent Pap tests (every three years) are considered acceptable when there is no access to HPV primary testing.

Depending on circumstances, over time, healthy cells may replace these transformed cells or they may continue growing abnormally and become cancerous.

Most cervical HPV infections do not lead to cervical cancer. The body is often capable of eliminating these infections on its own.

Other Squamous Cell Cancers and HPV

HPV infection is also associated with squamous cell cancers in other locations. They include cancers of the head and neck, the vulva, the penis, and the anus. In fact, some scientists estimate that four out of every five cancers are caused by HPV .

Fortunately, HPV-associated cancers have been found to be more treatable than other squamous cell cancers — at least in the head and neck.

How do people get HPV-related cancers? For all of the sites mentioned above, HPV transmission is thought to be sexual. Oral, anal and vaginal sex can transmit HPV, but transmission does not require intercourse. Skin-to-skin transmission of HPV is possible.

A Word From Verywell

It's understandable that abnormal Pap smear results can seem upsetting. However, remember that many cervical changes go away on their own. This isn't just true for ASCUS smears. Many pre-cancerous lesions also go away on their own within a year or two.

Therefore, if you have an abnormal Pap smear, resist the urge to panic! Instead, talk to your healthcare provider about the steps you want to take going forward. Your healthcare provider may advise treatment. However, they may also take a wait and see approach.

A large research study has shown that women who have a follow-up Pap smear six months after an abnormal low-grade smear do just as well as those who receive a colposcopy and biopsy. These are more invasive forms of testing and treatment.

The risk of HPV infection can also be reduced by vaccination. Cervarix and Gardasil are two vaccines that have been shown to reduce the risk of HPV infection. However, they are most effective when they are given before young people become sexually active.

If you are a young adult or the parent of a young adult, talk to your healthcare provider about whether the HPV vaccine is a good option for you. The HPV vaccine is currently recommended as a routine vaccination for young men and women between the ages of 11 and 12. It can be given up until age 27, depending on the circumstances.

The U.S. Centers for Disease Control and Prevention and the ACS recommend HPV vaccination begin between ages 11 and 12 and 9 and 12, respectively. Though the vaccine is approved for people 9 through 45, it's most effective when administered early. People over 26 generally do not benefit form the vaccine as they're likely to have een infected by HPV by that point. The ACS recommends against HPV vaccination for most people older than 27 due to low effectiveness and a vaccine shortage. 

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5 Sources
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  1. The Skin Cancer Foundation. Squamous cell carcinoma. Last reviewed May 2019.

  2. So KA, Kim MJ, Lee KH, et al. The impact of high-risk HPV genotypes other than HPV 16/18 on the natural course of abnormal cervical cytology: A korean HPV cohort studyCancer Res Treat. 2016;48(4):1313–1320. doi:10.4143/crt.2016.013

  3. Fontham ETH, Wolf AMD, Church TR, et al. Cervical cancer screening for individuals at average risk: 2020 guideline update from the american cancer society. CA Cancer J Clin. 30 Jul 2020. doi:10.3322/caac.21628

  4. R. Abu-Eid and G. Landini. Tissue architecture and cell morphology of squamous cell carcinomas compared to granular cell tumours’ pseudo-epitheliomatous hyperplasia and to normal oral mucosae. in Losa GA et al. (ed) (2005) Fractals in Biology and Medicine

  5. Saslow D, Andrews KS, Manassaram-baptiste D, Smith RA, Fontham ETH. Human papillomavirus vaccination 2020 guideline update: American cancer society guideline adaptation. CA Cancer J Clin. 2020 Jul;70(4):274-280. doi:10.3322/caac.21616

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