Merkel Cell Carcinoma Causes and Risk Factors
Merkel cell carcinoma (MCC) is a relatively uncommon and aggressive type of skin cancer that results from the uncontrolled growth of touch receptor cells (Merkel cells) in the thin, outermost layer of skin (epidermis). Usually, the first symptom is a firm, shiny, painless growth on an area of sun-exposed skin, such as the face or neck.
Because MCC often develops in areas of the body that are regularly exposed to natural or artificial sources of ultraviolet (UV) light—such as sunlight and the light emitted by indoor tanning devices—scientists believe UV exposure plays a role in its development.
Usually, treatment involves surgery to remove the tumor followed by radiation therapy to destroy any remaining cancer cells and help prevent a recurrence. In some cases, chemotherapy or immunotherapy may be considered, especially if the cancer has spread.
What causes Merkel cell carcinoma?
MCC is primarily caused by harmful cellular DNA changes that lead to uncontrolled cell growth and proliferation. All cells in the body, including skin cells, are programmed with instructions to grow at a specific rate and die when their life cycle is complete. If the DNA of a healthy cell is damaged, it may provide the cell with faulty instructions, causing the cell to lose its ability to replicate in a controlled manner. The damaged cell may also produce multiple copies of itself, creating small clusters of abnormally functioning cells (tumors), which can potentially invade other tissues and organs.
Scientists have identified two key factors that may contribute to the development of Merkel cell carcinoma:
- Merkel cell polyomavirus (MCPyV) – Up to 80% of MCC cases are linked to MCPyV, which integrates its DNA into the host cell and alters its function.
- Genetic mutation – Some MCC cases are traced to a spontaneous (non-inherited) gene mutation that damages the DNA of skin cells.
Both mechanisms involve the disruption of normal skin cell regulatory pathways, leading to the rapid and aggressive cell growth that is characteristic of Merkel cell carcinoma.
What are the risk factors for Merkel cell carcinoma?
Risk factors are characteristics, behaviors and exposures that can increase the risk of developing MCC. Some risk factors can be controlled, while others cannot.
Merkel cell carcinoma risk factors that can be controlled
Exposure to UV light is believed to be a significant—and largely controllable—risk factor for most skin cancers, including MCC. UV rays can damage the DNA inside skin cells. Over time, the damage may interfere with the orderly growth of the cells, leading to cancer.
Merkel cell carcinoma risk factors that cannot be controlled
Certain MCC risk factors cannot be controlled, such as:
- A personal history of skin cancer – MCC is strongly associated with basal cell carcinoma and squamous cell carcinoma.
- Weakened immunity – The body’s immune system, which protects against harmful invaders (including cancer), can lose its effectiveness due to human immunodeficiency virus (HIV), certain lymphomas and immunosuppressive medications taken to prevent organ rejection after a transplant.
- Light-colored skin – Dark skin may provide some level of protection against damaging UV light.
- Advanced age – While Merkel cell carcinoma can occur at any age, it is most often diagnosed after age 50.
Can Merkel cell carcinoma be prevented?
MCC cannot be prevented. However, the risk can be greatly reduced by minimizing exposure to UV light. This includes wearing sunscreen, protective clothing and a hat when spending time outdoors and never using indoor tanning devices, such as beds, booths and lamps.
Additionally, regular skin checks for unusual moles or skin growths can promote early detection and treatment of Merkel cell carcinoma and other skin cancers.
Frequently asked questions (FAQs) about Merkel cell carcinoma causes and risk factors
The following FAQs-related article provides additional information about Merkel cell carcinoma causes and risk factors:
Benefit from world-class care at Moffitt Cancer Center
Skin cancer research is a key area of focus at Moffitt, and we have a robust portfolio of clinical trials. Our Cutaneous Oncology Program is home to a multispecialty team of scientists and clinicians who are continually improving the preventive, diagnostic and treatment techniques for MCC, helping many patients achieve the best possible outcome and quality of life.
If you would like to learn more about Merkel cell carcinoma causes and risk factors, you can request an appointment with a specialist in Moffitt’s renowned Cutaneous Oncology Program by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.
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