Squamous Epithelial Cells

What they are, why they're tested for, and related cancers

Squamous epithelial cells are a type of flat 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 epithelial 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.

Treatment

Treating abnormal squamous epithelial cells depends on the Pap smear diagnosis. There is often no need to treat LSILs as they usually normalize on their own. Treating HSILs may also not be necessary, as HSILs can go away on their own, especially in those in their younger twenties.

But when abnormal epithelial cells appear to have a risk of being concerning or cancerous, treatment involves exercising or removing the abnormal tissue. A common excisional method is known as a loop electrosurgical excision procedure (LEEP), where abnormal cells are cut away by a wire loop that's heated with an electric current.

Urine Test for Epithelial Cells

A urinalysis is a standard test that analyzes the substances in your urine. This includes the amount of epithelial cells your urine contains.

While it's normal to have small amounts of epithelial cells in your urine, large amounts may signify something is wrong, such as an infection or another medical condition.

What to Expect

A urine sample is needed for an epithelial cells in urine test. You will receive a container where the urine is collected and given instructions on how to take the sample to ensure it does not get contaminated.

Typically, you will not need to fast or do other preparations before taking the test unless instructed by your healthcare provider.

Results

Results of cell amounts are usually reported as approximates, such as "few," "moderate," or "many" cells. "Few" cells mean that your epithelial cell numbers are considered to be in the normal range, while "moderate" or "many" cells may be a sign of a medical condition like:

  • Urinary tract infection
  • Liver disease
  • Yeast infection
  • Cancer

Know that having results in the abnormal range doesn't always mean you have a medical condition. Your healthcare provider will typically order more tests to form a final diagnosis.

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, 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. 

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  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. UpToDate. Follow-up of high-grade or glandular cell abnormal Pap tests.

  6. MedlinePlus. Epithelial cells in urine.

  7. 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

Additional Reading

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.