Squamous cell carcinoma is the second most common form of skin cancer after basal cell carcinoma. It is considered locally invasive, and, although uncommon, can spread beyond the skin into other organs of the body if left untreated. The cancer develops from squamous cells which are thin, flat cells found on the surface of the skin, in the lining of hollow organs and in the respiratory and digestive tracts.
It usually shows up on areas of the skin that are exposed to the sun, such as the face, ears, lips, arms, legs and tops of hands, but it can also more rarely appear on areas not exposed to the sun, including the lower lip, genitals, lungs and oesophagus.
How does squamous cell carcinoma form?
Squamous cell carcinoma occurs when squamous cells begin to grow uncontrollably in the top layers of the skin, known as the epidermis. This uncontrolled growth is usually a result of cellular damage often caused by chronic exposure to UV rays over time. This means that people who use tanning beds or who have spent a lot of time outdoors unprotected are at a much higher risk of developing squamous cell carcinoma as well as those with pale skin types. Cellular damage can also more rarely be caused by other factors such as exposure to toxic substances or a weakened immune system. This puts people who have a history of actinic keratosis, those who have had some form of the human papillomavirus or have been badly burned in the past at a higher risk for developing the cancer as well.
Where does squamous cell carcinoma form?
Researchers have been working to determine which cells trigger squamous cell carcinoma to form. Some evidence points to hair follicle stem cells as the origin point. Looking even closer, within these cells, researchers from UCLA discovered that the mother stem cells can develop the cancer while the progeny cells cannot. This distinction between two different types of cells in the skin is providing researchers with new research targets. Looking into why one cell can develop the cancer and the other cannot is a potential avenue to treatments that may be able to prevent the cancer before it starts.
If you have any suspicions about a mole, spot or growth, have it checked out as soon as possible.