How Squamous Cells Can Be Potentially Affected by HPV

Pap smear/gynecologist exam

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A squamous cell is a type of epithelial cell. These cells are found in many areas of the body. People often think of epithelial cells as "skin" cells. However, that's misleading. Epithelial cells can actually be found covering many layers of the human body — not just the outside.

Squamous cells are flat epithelial cells. In contrast, cuboid epithelial cells are square, and columnar epithelial cells are rectangular.

Squamous cells are found in a variety of different parts of the body. You can find squamous cells in the mouth, on the lips, and on the cervix. They are also seen in the middle layers of the skin.

Squamous cells are pretty utilitarian epithelial cells. They form flat sheets of cells. As such, they are useful as tissue coverings just about everywhere.

Most people only become familiar with the term squamous cell when they are diagnosed with a squamous cell carcinoma.

This is a type of cancer that affects the squamous layers of the epithelium. Squamous cell carcinomas are the most common cancer of the oral cavity. These cancers are also commonly found in the cervix and the skin.

Squamous Cells and Cervical Cancer

There is another reason that women may be familiar with the term squamous cell. They may have heard the words after getting a Pap smear result. Several diagnoses that might be given in response to a Pap smear use the word squamous.

For example, ASCUS (Atypical Squamous Cells of Undetermined Significance). This diagnosis is exactly what it sounds like. It means a Pap smear had unusual cells, but they were not clearly good 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. However, these cells have not necessarily become cancerous. In fact, low-grade squamous intraepithelial lesions (LSIL) often heal themselves without any 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 HPV. Human papillomavirus infects and transforms the squamous cells of the cervix. It can also infect and transform the cells of other tissues in the body.

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 sex and anal sex can transmit HPV, in addition to vaginal intercourse.

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 doctor about the steps you want to take going forward. Your doctor 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 doctor 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.

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  1. 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

  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

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