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Is Skin Cancer Genetic or Environmental?

March 2, 2018

Roughly half of all Americans who live to the age of 65 will have some type of skin cancer at least once during their lifetime. Skin cancer is very common and is almost always the result of the damaging effects of the sun. But is UV exposure the only way to get skin cancer? Is skin cancer genetic?

The answer is yes and no. Most skin cancer is environmental, but some melanomas can be passed down genetically. Here’s what you need to know:

The Most Common Types of Skin Cancer

More than 90% of all skin cancer is caused by long-term exposure to UV radiation. The most common types of skin cancer are basal cell carcinoma and squamous cell carcinoma.

Basal cell carcinoma is the most common and typically develops in people with fair skin. Almost 1 million new cases of basal cell carcinoma are diagnosed each year in the U.S. This cancer typically begins as a small, shiny bump on the face, though it can occur on any part of the body.

Squamous cell carcinoma is the second most common form of skin cancer and develops in the squamous cells that make up the outer layer of skin. It is most often found on areas of the skin most exposed to the sun and can appear as a firm, red nodule, a flat sore with a scaly crust, a new sore or raised area on an old scar or ulcer, or a rough scaly patch. If left untreated, squamous cell carcinoma can spread to other parts of the body and cause serious complications.

Basal cell carcinoma and squamous cell carcinoma are rarely life-threatening and can usually be removed with cryosurgery, curettage, simple excision, Mohs surgery or radiation therapy in some cases.

Melanoma, the most deadly type of skin cancer, is also the rarest. Melanoma presents as a new spot on the skin or a spot that changes in shape, size or color. It could be a sore that doesn’t heal or a mole that is asymmetrical, nonuniform in color, has a ragged border or simply doesn’t look like the other moles on your body.

“Melanoma accounts for less than 10% of all skin cancer cases but causes more than 50% of skin cancer deaths,” says Dr. Matthew HoffmannU.S. Dermatology Partners of Longview. “Many cases of melanoma can be linked to exposure to UV rays, but family history and genetics also play a role in an individual’s risk.”

Familial Melanoma

Approximately one in 60 people will develop invasive melanoma during their lifetime and almost all of these cases are related to environmental factors such as sun exposure. However, the risk of melanoma can be passed down from generation to generation, though it is somewhat rare. Around 5-10% of all melanoma cases are considered genetic or inherited.

Around 8% of those newly diagnosed with melanoma have a first-degree relative (a parent, sibling or child) with melanoma. Some 1% to 2% of those newly diagnosed have two or more close relatives with melanoma.

Parents with a specific genetic mutation have a 50-50 chance of passing on the disposition to developing melanoma to their children. One type of hereditary melanoma — familial atypical mole-melanoma syndrome (FAM-M syndrome) — is caused by mutations in the CDKN2A gene on chromosome 9, also called the “p16 mutation” and is present in up to 40% of familial cases of melanoma.

Typically, every cell has two copies of each gene. One is inherited from the mother and one is inherited from the father. With familial melanoma, a mutation happens in just one copy of the gene, so a parent with a mutation can pass along a copy of his or her normal gene or copy the gene with the mutation. If a parent has a mutation, the child has a 50% chance of inheriting the mutation.

There are other inherited genes associated with an increased risk of melanoma including the CDK4 gene and BRCA2, a hereditary breast cancer gene.

If you have a family history of invasive melanoma (two or more first-degree relatives with melanoma or a single family member with multiple melanomas), you can have genetic testing done in a genetics clinic for mutations in the CDKN2A gene. However, most families have not yet identified that they have a genetic mutation. A genetic counselor or physician can help identify this and other genes that could increase skin cancer risk.

Families with familial melanoma and CDKN2A mutations also have a slightly increased risk of developing pancreatic cancer, and individuals with the BRCA2 mutation are at an increased risk for breast and ovarian cancer in women, prostate cancer in men and pancreatic cancer in both men and women.

Importance of Cancer Screening

If you have a parent, sibling or child with a history of melanoma, you should carefully monitor your skin.

“The American Academy of Dermatology recommends that you have your skin screened every six months to one year to make sure there are no worrisome spots and have an immediate check if you notice any moles changing in size, shape or color,” says Dr. Hoffmann. “If melanoma runs in your family, children should begin skin screenings by the age of 10, and everyone in the family should perform self-exams at home to monitor any changes. As always, everyone should also wear sunscreen.”

Do you know your risk of melanoma and other types of skin cancer? To learn your risk and what you can do to prevent skin cancer, make an appointment with one of our board-certified dermatologists today.

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