Skin Cancer: Merkel Cell Carcinoma

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What Is Skin Cancer - Merkel Cell? TOPICS

What is cancer?

Research into the causes, prevention, and treatment of Merkel cell carcinoma (MCC) is under way in many medical centers throughout the world.

Causes of MCC

Scientists have made a great deal of progress in recent years in learning how ultraviolet (UV) light damages the DNA in skin cells, which might cause them to become cancer. Researchers are working to apply this information to help prevent and treat these and other skin cancers.

Researchers are also learning more about the Merkel cell polyomavirus (MCV), which has been found in nearly all MCC tumors. It’s not yet clear exactly how damage from UV light, infection with MCV, and changes in the body’s immune system might interact to cause MCC, but this is an active area of research.

Prevention of MCC

Most skin cancers, including many MCCs, can be prevented. The best way to reduce the number of skin cancers and the pain and loss of life from this disease is to educate the public, especially parents, about skin cancer risk factors and warning signs. It’s important for health care professionals and skin cancer survivors to remind others about the dangers of excess UV exposure (both from the sun and from man-made sources such as tanning beds) and about how easily they can protect their skin from UV radiation.

MCC can often be detected early, when it’s most likely to be cured. Monthly skin self-exams and awareness of the warning signs of MCCs and other skin cancers can be helpful in finding them when they are at an early, curable stage.

The American Academy of Dermatology (AAD) sponsors annual free skin cancer screenings throughout the country. Many local American Cancer Society offices work closely with AAD to provide volunteers for registration, coordination, and education efforts related to these free screenings. Look for information in your area about these screenings or call the American Academy of Dermatology for more information. Their phone number and website address are listed in the “Additional resources” section of this document.


While early-stage MCCs can often be cured, more advanced MCCs can be much harder to treat. It’s been hard to study the best way to treat these cancers because they are not common. But in recent years, doctors have begun to look at newer types of treatment for this disease.


This type of treatment helps the body’s immune system attack cancer cells more effectively. Doctors are hopeful this approach might be helpful against MCC, especially because this cancer now appears to be linked to infection with a virus (MCV).

An example of immunotherapy is a drug called ipilimumab (Yervoy). This drug targets CTLA-4, a protein in the body that normally suppresses immune system cells called T cells, which might help cancer cells survive. By blocking CTLA-4, ipilimumab is thought to boost the immune response against cancer cells in the body. This drug has already been shown to help people with advanced melanoma of the skin, and it’s now being studied for use in MCC as well.

Other drugs that help boost the immune system are also being studied. In particular, drugs that block the PD-1 or PD-L1 proteins have recently shown great promise against several different types of cancer, and might eventually be shown to help against MCC.

Another approach now being tested is to remove T cells from a person’s blood and expose them in the lab to parts of the Merkel cell polyomavirus (along with chemicals to help activate the T cells). The cells are then infused back into the body. The hope is that these cells will now seek out and attack MCC cells in the body. This approach is still in early phases of testing.

Hormone-type drugs

MCC is a type of neuroendocrine tumor, which means its cells share features with those that normally make hormones in the body. Doctors are now testing whether drugs that affect hormone-making cells might be helpful against MCC.

An example is pasireotide (Signifor), which is a type of drug known as a somatostatin analog. Some new drugs pair a somatostatin analog with a radioactive atom. These drugs should bind to the cancer cells, delivering the radiation to those cells and limiting the effects on normal cells. Research testing these types of drugs against MCC is still in very early phases.

Other new drugs

Newer drugs called targeted therapies may someday be shown to help treat MCC. Targeted therapies attack parts of cancer cells that make them different from normal, healthy cells. Each type of targeted therapy works differently, but they alter the way a cancer cell grows, divides, repairs itself, or interacts with other cells in some way. Targeted drugs are already used to treat some types of cancer, and some are now being studied for use against MCC.

Last Medical Review: 12/31/2013
Last Revised: 12/31/2013