Causes and Risk Factors for Merkel Cell Carcinoma

Overview

Merkel Cell Carcinoma (MCC) is a type of skin cancer that originates in the Merkel cells, which are located at the bottom of the outer layer of the skin called the epidermis. These cells are connected to nerve endings that give us our sense of touch. MCC occurs when something goes wrong within these cells, causing them to grow uncontrollably.

While researchers haven't identified the exact cause of MCC, there are several known risk factors associated with this type of cancer. These include:

• Age: MCC is more common in older adults, particularly those over 50 years old.
• Sun exposure: Excessive exposure to the sun's harmful ultraviolet (UV) rays is a risk factor for MCC. Long-term sun exposure can increase the chances of developing this type of skin cancer.
• Tanning beds: The use of tanning beds, which emit UV radiation, can also increase the risk of MCC.
• Light-colored skin: People with light-colored skin have a higher risk of developing MCC compared to those with darker skin tones.
• Weakened immune system: Having a compromised immune system, such as individuals with HIV or chronic leukemia, or those taking immunosuppressive drugs, increases the risk of MCC.
• Merkel cell polyomavirus (MCPyV): About 80% of MCC cases are triggered by an infection with a virus called MCPyV. Most people are infected with this virus at a young age.

It's important to note that while these risk factors can increase the likelihood of developing MCC, they do not guarantee that someone will develop the disease. Researchers continue to study MCC to better understand its causes and develop effective prevention and treatment strategies.

Non-modifiable Risk Factors (Risk Factors You Can't Change)

Non-modifiable risk factors for Merkel Cell Carcinoma (MCC) are factors that cannot be changed or altered. These risk factors include:

• Age: Advanced age is a non-modifiable risk factor for MCC. The risk of developing MCC increases with age, especially in individuals over the age of 50.
• Fair skin: People with fair skin have a higher risk of developing MCC compared to those with darker skin tones. Fair skin is more susceptible to the damaging effects of ultraviolet (UV) radiation from the sun, which can increase the risk of developing skin cancers, including MCC.
• Chronic immunosuppression: Chronic immunosuppression, such as in individuals with chronic lymphocytic leukemia or HIV infection, is a non-modifiable risk factor for MCC. A weakened immune system can make it harder for the body to fight off cancer cells and increase the risk of developing MCC.
• Genetic predisposition: Certain genetic factors may increase the risk of developing MCC. Individuals with a family history of MCC or other related cancers may have an increased risk.

It's important to note that having these non-modifiable risk factors does not guarantee that someone will develop MCC, and not having these risk factors does not mean someone is completely protected from developing it. It's always a good idea to discuss any concerns or potential risk factors with a healthcare provider.

Modifiable Risk Factors (Factors You May Be Able to Change)

Modifiable risk factors are factors that can be changed or influenced. These are:

• Sun exposure: Being exposed to a lot of natural sunlight or artificial sunlight from tanning beds can increase the risk of MCC. It is recommended to limit sun exposure, especially during peak hours when the sun is strongest (usually between 10 am and 4 pm). Wearing protective clothing, such as hats and long sleeves, and using sunscreen with a high SPF can help reduce the risk.
• Immune system suppression: Having a weakened immune system can also be a risk factor for MCC. This can occur due to certain medical conditions like chronic lymphocytic leukemia or HIV infection, or as a result of taking medications that suppress the immune system, such as those used after organ transplantation. If you have a weakened immune system, it's important to discuss with your healthcare provider about ways to manage your risk.
• Psoralen and ultraviolet A (PUVA) therapy: This type of therapy is sometimes used for treating psoriasis. It involves taking a medication called psoralen and then being exposed to ultraviolet A (UVA) light. While PUVA therapy can be beneficial for psoriasis, it may also increase the risk of developing MCC. If you are undergoing PUVA therapy, your healthcare provider will monitor you closely for any signs or symptoms of MCC.

It's worth noting that having these modifiable risk factors doesn't mean you will develop MCC and not having them doesn't guarantee that you won't develop it either. It's always important to take steps to protect your skin from excessive sun exposure and to discuss any concerns or potential risk factors with your healthcare provider.

Reducing Risks

To prevent or reduce the chances of getting MCC, there are several actions a person can take to modify their risk factors:

• Avoid sun exposure: One of the most important ways to reduce the risk of MCC is to limit sun exposure. This includes avoiding the sun during peak hours, typically between 10AM and 4PM when the sun's rays are strongest. If you need to be outside during these hours, it's important to wear protective clothing such as long sleeves, pants, a hat with UV protection, and sunglasses.
• Use sunscreen: Applying sunscreen regularly is crucial for protecting your skin from harmful UV rays. Choose a broad-spectrum sunscreen with a high SPF (sun protection factor) and apply it generously to all exposed areas of skin. Be sure to reapply every two hours or more frequently if you're sweating or swimming.
• Avoid tanning beds: Tanning beds emit harmful UV radiation that can increase the risk of developing skin cancer, including MCC. It's best to avoid using tanning beds altogether.
• Perform regular skin self-examinations: By performing a monthly skin self-examination, you can help detect any potential problems early on. During this examination, thoroughly check your skin for any abnormal lumps or spots that are new or changing in size, shape, or color. If you notice anything unusual, make an appointment with your doctor or dermatologist for further evaluation.
• Maintain a healthy lifestyle: While not directly related to MCC, maintaining a healthy lifestyle can contribute to overall well-being and potentially reduce the risk of developing various types of cancer. This includes:
  • Maintaining a normal body weight
  • Eating a balanced diet rich in vegetables and fruits
  • Managing stress
  • Engaging in regular physical activity
  • Minimizing alcohol intake
  • Quitting smoking (including second-hand smoke exposure)
  • Reducing exposure to environmental toxins

It's important to note that while these actions can help reduce the risk of developing MCC, they do not guarantee complete prevention. It's always recommended to consult with your doctor or dermatologist for personalized advice and guidance based on your individual circumstances.