Melanoma (Landi, 2020) – Is melanoma genetic?

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Nebula Genomics DNA Report for Melanoma

Is melanoma genetic? We created a DNA report based on a study that attempted to answer this question. Below you can see a SAMPLE DNA report. To get your personalized DNA report, purchase our Whole Genome Sequencing!

Sample report on melanoma by Nebula Genomics
Sample variants on melanoma by Nebula Genomics
To learn more about how Nebula Genomics reports genetic variants in the table above, check out the Nebula Research Library Tutorial.

What is Melanoma? (Part 1 of Is melanoma genetic?)

Melanoma, also known as cutaneous melanoma, is a skin cancer that forms in the pigment cells called melanocytes and can appear anywhere on the skin. These cells produce melanin, which gives the skin its color. Many melanomas develop from existing moles. Changes in a mole’s size, edges, color, itchiness, or skin breakdown can all indicate a case of cancer. Although not as common, the condition can also form in the eyes or internally in the nose or throat. 

Melanoma on the face
Melanoma growth after one year. Wikipedia. CC-Attribution-Share Alike 4.0 International.

Typically, melanoma is caused by exposure to UV light, either radiation from the sun or from artificial lights like tanning beds. Doctors can diagnose the condition through biopsy and analysis of skin lesions that may be suspected to be cancerous. Most cases can be successfully treated if early detection is made. Surgery to remove the affected skin area is performed to treat melanoma. In most cases in which the cancer has not spread, surgery results in curing the cancer. 

Even though localized cancer has a high survival rate, melanoma is still the most dangerous type of skin cancer. The best way to protect yourself from this condition is by using sunscreen and avoiding direct UV light. 

The other two types of skin cancer are squamous cell carcinoma and basal cell carcinoma. Like melanoma, they also occur in the top layer of the skin. 

Is Melanoma Genetic?

As a cancer, all melanomas are ultimately caused by genetic mutations that either keep on oncogenes (genes that cause cancer) or by turning off tumor suppressor genes (genes that prevent cancer). These genetic changes can be either acquired during life or inherited from your parents. The most common genetic variations associated with melanoma are acquired, but a few can be inherited and melanoma can run in families. 

A genetic counselor can help assess your risk, especially if you have a family history of melanoma.

Overall, about 10% of melanomas are caused by an inherited mutation that occurs as an autosomal dominant gene. This means that the mutation occurs in only one copy of the gene. 

About 8% of people diagnosed with melanoma have a first-degree family member with the condition. A much smaller percentage, about 1% to 2%, has 2 or more close relatives with the disease.

BRAF: This acquired genetic mutation is found in half of all melanomas. BRAF is an oncogene involved in an important signaling pathway that instructs a cell to grow, divide, move, and destruct. 

CDKN2A: This gene is needed for the production of several proteins, especially the p16 and p14 proteins. These are tumor suppressor proteins.

Familial melanomas most often are caused by changes in tumor suppressor genes. To date, two gene mutations have been identified as increasing the risk of familial malignant melanoma: the CDKN2A and CDK4 genes. Both of these genes play important roles in controlling when cells divide. They may also be associated with pancreatic cancer.

Some people inherit a condition called xeroderma pigmentosum (XP). It involves a change in the XP (ERCC) genes, which normally help to repair damaged DNA inside the cell. DNA in skin cells of these patients has a more difficult time repairing damage after UV exposure, increasing the risk of developing melanoma. 

Other genes can also influence your risk. For example, people with red hair carry a genetic variant on the gene MC1R that puts them at a high risk of skin cancers equal to an extra 21 years of sun exposure.

Genetic testing and genetic counseling can help you assess whether you may have a higher risk of developing the condition. 

Epidemiology (Part 3 of Is melanoma genetic?)

According to the Centers for Disease Control and Prevention (CDC), about 83,000 new cases of melanoma occurred in the United States in 2018. It is currently the sixth most common cancer in terms of new cases. 

Based on data between 2012-2016, the highest incidence rate was among non-Hispanic white males, and the lowest rate was among black females. During the same time period, about 9,008 people died from melanoma in the United States each year.

Although the incidence of cancer has been increasing in the United States, the death rate has declined. Experts attribute this observation to new and more effective treatment options.

Symptoms (Part 4 of Is melanoma genetic?)

Anything unusual on the skin, including moles, sores, lumps, blemishes, markings, or changes in the way an area of the skin looks or feels can be an indication of melanoma or other skin cancer.  

Melanoma is often associated with changes in moles on the skin. Most people have some moles either at birth or gained in childhood and most of them are harmless. Moles tend to be evenly colored, round or oval, and flat or raised. 

According to the American Cancer Society, the most important warning sign of melanoma is a new spot on the skin or a spot that is changing in size, shape, or color. You may also notice a spot that is different from the other spots on your skin. More health information can be found on their website. 

They also recommend the ABCDE rule for assessing whether a mole could be the sign of melanoma including:

  • Asymmetry: One half of a mole or birthmark does not match the other
  • Border: The edges are irregular, ragged, notched, or blurred
  • Color: The color is not the same all over and may include different shades of brown or black, or sometimes with patches of pink, red, white, or blue
  • Diameter: The spot is larger than 6 millimeters across
  • Evolving: The mole is changing in size, shape, or color
A mole that shows characteristics of melanoma
A melanoma with ABCDE characteristics. Wikipedia. CC-Attribution-Share Alike 4.0 International.

If you notice any of these changes, it is important to talk with your doctor. You should also be aware of the small chance of melanomas occurring on areas other than the skin, including under nails, inside the mouth, or in the eye. Acral lentiginous melanoma is a rare type that occurs on the soles of the feet or palms of the hand. 

It can be difficult to distinguish normal moles from cancerous ones, especially in areas that are difficult to see, which is why it’s important to speak with a healthcare professional at the first warning sign. Most cases that are diagnosed early can be treated.

Causes (Part 5 of Is melanoma genetic?)

Experts are unsure why some moles and spots become cancerous while most others do not. There are several risk factors that may put certain groups of people at greater risk. In most cases, these risk factors cause acquired genetic mutations, changes in the DNA that occur over a lifetime and are not passed down to children. 

Sun rays
Melanoma is associated with UV light exposure. Public Domain Pictures. 

Cancer is often influenced by environmental factors. The greatest risk factor for melanoma is direct exposure to UV light that damages DNA in skin cells. This damage can cause some genes to no longer function correctly, leading to cancer. Sources of UV light are the sun and artificial light, like tanning beds. 

For many people, the cancer appears years after the exposure. For example, many children and young adults are exposed to a lot of sunlight which only appears as melanoma later in adulthood. Sunscreen is a proven protection against the damaging effects of UV light and should be used as recommended, even on cloudy days. 

Diagnosis (Part 6 of Is melanoma genetic?)

Melanoma is initially diagnosed through examination of the skin. Abnormal spots or moles are the first signs of the condition and can usually be identified by a medical examiner. If an area seems suspicious, your doctor will normally perform a biopsy to confirm the presence of skin cancer. This procedure involves taking a sample of the skin and analyzing it in a lab. 

Usually, the whole growth is removed either through a punch biopsy (a circular blade pressed against the skin) or excisional biopsy (a scalpel is used to remove the entire mole).

A punch biopsy diagram
A punch biopsy. Wikipedia. CC-Attribution-Share Alike 4.0 International.

If a biopsy determines the presence of melanoma, your doctor will recommend additional tests to determine the cancer’s extent. 

Thickness tends to be an indicator of how serious the cancer is. While thinner cases can be removed by surgery, a thicker case may be indicative of more serious disease or cancer spread. 

If the doctor suspects the cancer has spread to the lymph nodes they may perform a sentinel node biopsy. During this procedure, a dye is injected at the site where the cancer was present. It will eventually leak into lymph nodes, of which a sample is removed. If the dyed lymph node does not contain cancer, it is unlikely that it will spread to other nodes.

In more serious cases, imaging tests like X-rays, CT scans and positron emission tomography (PET) scans can search for cancer in other parts of the body. These tests are not usually performed when the melanoma is small and is unlikely to have spread past the skin. 

Stages of melanoma are diagnosed as I through IV. Stages 0-I are easily treatable, while stage IV indicates that the cancer has metastasized to other parts of the body. The stage of the cancer largely determines diagnosis and treatment. 

Treatment (Part 7 of Is melanoma genetic?)

Treatment of melanoma will depend on a number of factors such as the type of melanoma, stage of the cancer, the patient’s overall health, and personal preference. 

For small and very thin melanomas, the only treatment needed may be to remove the affected area through biopsy. Removing the cancer will generally cure the condition.

More advanced treatment may be needed if the cancer has spread beyond the skin. These options may include:

Surgery

Surgery may be recommended to remove the affected lymph nodes. Additional treatment after surgery may be recommended.

Immunotherapy

This treatment may be recommended after surgery if the cancer has spread, especially if the melanoma could not be removed completely. There are different options for immunotherapy although they all serve to help the body’s immune system better recognize cancer cells and destroy them.

Targeted therapy

This is another treatment that may be recommended after surgery if the cancer has spread. This medicine takes advantage of targeted specific weaknesses on cancer cells and destroys them in areas far away from the skin. 

Radiation therapy

This therapy is normally used for cancer that is not able to be removed completely with surgery. It involves using high-powered energy beams, such as X-rays and protons, to kill cancer cells. It can also help relieve symptoms as well as treat the cancer. 

Chemotherapy

This treatment uses medications designed to kill cancer cells. These drugs can be given either intravenously or orally.

If you liked this article, you should check out our other posts in the Nebula Research Library!