Melanoma is often linked to inherited genetic mutations or exposure to UV light. Your risk of developing this type of skin cancer is higher if you have light skin, a family history, or a compromised immune system.

Healthcare professionals haven’t established exactly what causes melanoma. Although it often develops in areas frequently exposed to UV light, like your face or chest, it can also develop in areas that rarely see sunlight, like the inside of your nose.

Experts may sometimes identify gene mutations that run through families and are linked to melanoma risk. When melanoma is associated with inherited genes, you may find more than one family member, often in different generations, develops it.

The two main causes of melanoma are UV light exposure and predisposing genes.

Like other cancers, melanoma skin cancer develops when cells replicate out of control due to changes in their DNA. Inherited gene mutations or mutations that develop throughout your life can cause DNA changes.

Inherited gene mutations

According to a 2021 review, about 10% of melanomas are linked to genes passed through families. These cancers are called familial melanomas.

Familial melanomas often develop at a younger age, the review notes. The inherited gene mutation remains unidentified in many families, but some genes that have been linked to familial melanoma include:

  • CDKN2A
  • MC1R
  • MITF
  • CDK4
  • POT1
  • TERT
  • ACD
  • TERF2IP
  • BAP1

Acquired genetic mutations

Most melanomas aren’t associated with genes passed through families and develop due to gene mutations acquired throughout your life.

These mutations may develop seemingly randomly. Sometimes, the cancer can directly be attributed to damage from UV light exposure.

The most common genetic mutation seen in melanoma cells is in the BRAF gene. Other mutations linked to melanoma occur in the genes:

  • NRAS
  • CDKN2A
  • NF1

Although the underlying cause of melanoma often isn’t known, researchers have identified some factors that may increase your chances of developing this type of cancer.

According to the American Cancer Society, these factors include:

Frequent UV light exposure

Frequent UV light exposure can cause DNA damage that makes you more prone to developing skin cancer. Melanoma on your chest, back, and legs has been linked with frequent sunburns, especially in childhood.

Moles

People with many moles seem to be more likely to develop melanoma. Having atypical-shaped moles also may increase your risk.

People with the inherited condition dysplastic nevus syndrome have a very high lifetime risk.

Light skin, hair, and eyes

People with light skin, hair, and eye colors produce less pigment to protect their skin from the sun. Increased chance of melanoma is associated with people who have:

  • red or blond hair
  • blue or green eyes
  • skin that burns or freckles easily

Family history of melanoma

About 10% of people who develop melanoma have a family history. Your chances of melanoma double if you have a first-degree relative who’s had it, according to a 2021 review. First-degree relatives are:

  • children
  • parents
  • siblings

People with an inherited disorder called xeroderma pigmentosum also have an increased chance of skin cancer. This condition impairs the ability of the skin cells to repair DNA damage.

Personal history of skin cancer

You may be more likely to develop melanoma if you’ve previously had melanoma or another type of skin cancer. Melanoma can return after treatment or develop again somewhere else in your body.

Compromised immune system

If your immune system is compromised, your body’s ability to recognize and destroy cancer cells may be impaired. Some factors that may weaken your immune system include:

Aging

The risk of melanoma increases as you age, but it can still occur in younger people. Melanoma is one of the most common cancers in people under age 30.

Sex

Males may develop melanoma more often than females in the United States. However, this risk inverts for people under the age of 50.

The U.S. Preventive Services Task Force concludes that current evidence is insufficient to assess the benefits of regular skin cancer screenings for people who do not have any signs or symptoms of melanoma skin cancer.

The Skin Cancer Foundation recommends visiting a dermatologist once or more every year if you have a higher chance of developing skin cancer.

Regular skin screening may be important for people who have previously had skin cancer.

Checking for moles regularly can help you identify skin cancer early. You may do this by following the ABCDE rule:

  • Asymmetry: One half of the mole is unlike the other.
  • Border: The mole has irregular or blurred lines.
  • Color: The mole has varying colors within, such as tan, brown, blue, or white.
  • Diameter: The mole is larger than a pencil eraser (6 millimeters).
  • Evolving: The mole changes size, shape, or color over time.

Learn more about how to recognize melanoma.

Melanoma is primarily attributed to genes inherited from your parents or exposure to UV light. For many people, the underlying cause is never clear.

It’s important to visit a healthcare professional if you notice a spot on your skin you think may be caused by melanoma. Melanoma usually has a better outlook when it’s diagnosed early.