The Science of Melanoma

Melanoma’s having quite a year.

I was recently diagnosed with melanoma (I wrote a blog post about it–check it out here). I consider myself extremely lucky, as my melanoma was caught early. For others, the story does not have a happy ending. You’ve probably heard about former President Jimmy Carter, who recently disclosed he not only had melanoma, but it had spread to his liver and his brain. A few days ago, melanoma claimed neurologist and author Oliver Sacks as well.

Going through this journey, I had a lot of questions about melanoma. I decided to look into the science behind melanoma formation, melanoma growth, and the most current treatment options.

Our skin

Our skin is awesome. It helps us regulate our temperature, it is waterproof, it protects us from the elements, and helps us feel the world around us.

Skin cross section. Diagram courtesy of the National Institute of General Medical Sciences,

Skin cross section. Diagram courtesy of the National Institute of General Medical Sciences,

We have three layers of skin. The outer layer of skin is called the epidermis, which itself consists of different layers. The dermis lays underneath the epidermis. Underneath the dermis is a subcutaneous fat layer.

Melanocytes are tucked away in the basal layer of the epidermis. Melanocytes are a type of skin cells that give us our pigment. People who have darker skin have more pigment, or melanin, in their skin than lighter-skinned people. This is demonstrated in the diagram below:

Courtesy of Wikimedia commons

Courtesy of Wikimedia commons

Melanin protects the deeper layers of the skin from harmful ultraviolet radiation from the sun. When we are out in the sun, melanocytes produce more melanin, which causes the skin to darken or tan.

What is melanoma?

Cancer, by definition, is simply the uncontrolled division of cells in a certain part of the body. For example, someone with pancreatic cancer has pancreatic cells that keep dividing and dividing and the cell division doesn’t stop. In normal cells, the nucleus, or the cell “brain”, tells a cell when to stop dividing. Melanoma is simply cancer of the melanocytes.

Melanomas can develop anywhere, but they are most common on the trunk and back in men and on the legs in women. Melanoma is also most common in men over the age of 60, but in women, melanomas can occur at any age.

Both our environment and genetics play a part in determining if a person will have cancer.

Risk Factors

Fair skin, freckles, light hair

Melanin production is solely a function of our genes and our ancestors. For example, the vast majority of my ancestors are from northern Europe. There is less sun in northern Europe than, say, around the equator. I have less melanin than someone whose ancestors lived for many generations with lots and lots of sun. As I stated in an earlier post about my recent melanoma surgery, I am a phlebotomist’s dream but a dermatologist’s nightmare. I am only about 4-6 generations removed from my ancestors’ migration to America, and specifically Oklahoma, where I’m from originally. Evolution has not caught up with my ancestors’ moving habits.

Author Daniel Lieberman writes in his book The Story of the Human Body: Evolution, Health, and Disease, “Fair skin, for example, does not protect against sunburns but is an adaptation to help cells below the skin’s surface synthesize enough vitamin D in temperate habitats with low levels of ultraviolet radiation during the winter.” My fair skin + Oklahoma’s high UV = a greater chance of melanoma.

As an aside, let’s talk for just a minute about the ridiculousness of racism. Take everything I explained above and apply it to today’s world. Our skin is a function of our latitude. Nothing more. If you honestly think that someone’s skin represents anything other than that, such as intelligence or character, this science blog is not for you.

UV light exposure

Scientists believe that UV radiation in people with low levels of melanin can cause mutations.

For someone without a lot of melanin in their skin like me, UV radiation finds its way to more skin cells that are unprotected by melanin. Since UV radiation can cause mutations, this makes it more likely that these mutations will occur in light-skinned people.

UV radiation can come from either the sun or from tanning beds. Speaking of tanning beds…

Tanning beds

Scientific American published an editorial in the April 2015 edition titled “Ban the Tan“, which I highly encourage everyone to read. It stated that in 2014, a systematic review and meta-analysis of 88 studies concluded that tanning beds lead to over 10,000 new cases of melanoma every year in the U.S., Australia, and Europe, and as many as 450,000 cases of other types of skin cancer. In fact, the number of skin cancer cases linked to tanning beds every year is two times the number of lung cancer cases associated with smoking.

This is an absolutely jaw-dropping statistic.

I’ll talk more about tanning beds a little later on in this post.

Family history of melanoma

Around 10% of people who develop melanoma have a family history, especially with immediate family members.

Personal history of melanoma

If you’ve had a previous melanoma, like me, you have about a 5% chance of developing melanoma in the future.

Moles

Having a large number of moles also increases your chance of developing melanoma at some point.

How does melanoma develop?

Okay, so back to melanocytes. They’re mostly found in the epidermis of our skin, although they can be found in other places like our eyes and our hair. The basic function of melanocytes is to deliver melanin, or pigment, to epidermal cells. Melanocytes are dendritic, or branched, as you can see from the previous illustration.

Melanoma occurs when one or more melanocytes develop a mutation and begin to grow uncontrollably.

Once a mutation occurs, it doesn’t necessarily mean that melanoma or any other type of skin cancer will develop. But it does increase the chance that it will develop.

Here’s a great video that, while it does tend to get in the weeds a bit, does a great job at showing how a mutation can occur and how that mutation can translate into melanoma.

Once a melanocyte develops a cancerous cell, it is up to the body’s immune system to locate the cancerous cell and get rid of it. When cells divide normally (mitosis), the nuclei of the cells regulate how often the cell replicates, or makes a new copy. A cancer cell has no regulation. It is simply uncontrolled mitosis. Once a cancer starts to spread, it may evade the immune system’s detection because it is essentially still a cell that belongs to us. We made it, it just doesn’t know how to turn itself off.

How to spot melanoma

Dermatologists encourage people to use the ABCDEs of melanoma detection:

Look for these signs: Asymmetry, irregular Borders, more than one or uneven distribution of Color, or a large (greater than 6mm) Diameter. Finally, pay attention to the Evolution of your moles – know what’s normal for your skin and check it regularly for changes.

Courtesy of skincancer.org.

Courtesy of skincancer.org.

What happens after a melanoma begins to grow?

Normally, the cancerous melanoma cells are initially limited to the epidermis, the top layer of our skin. Some melanomas grow radially, or outward, in the beginning. If allowed to continue growing, the melanoma will begin to grow “downward”, or into the dermis. This is dangerous because if allowed to grow into the dermis, cancer cells can penetrate the lymphatic system and make their way to other parts of the body. At this point, the cancer has metastasized and it becomes extremely difficult to treat.

I was lucky enough to catch my melanoma early before it made its way past the epidermis. For others like President Carter, metastasis occurred and the cancer spread to other organs. This greatly diminishes the prognosis of a melanoma patient.

Is melanoma survivable?

Yes. Absolutely. Like most cancers, chances of survivability increase greatly if the cancer is caught early.

Stages of melanoma

After a melanoma is diagnosed, the next step is to determine the stage, which is a measure of how widespread the cancer is. Staging can be quite complicated, but the main things that determine staging are:

  • The thickness of the tumor
  • Where the tumor is located in the body
  • If the tumor is bleeding or ulcerated
  • If the tumor has spread into one or more lymph nodes
  • How quickly the cancer is reproducing (mitotic rate)
Stage 0 melanoma. Courtesy of cancer.gov.

Stage 0 melanoma. Courtesy of cancer.gov.

The staging ranges from 0 to 4. If a melanoma stays within the epidermis, is not ulcerated, and has not spread to any other parts of the body, this melanoma is classified as stage 0. As you can see from the illustration at left, this melanoma has only grown radially across the surface of the skin and has not grown deeper into the dermis.

Stage 1 Melanoma. Courtesy of cancer.gov.

Stage 1 Melanoma. Courtesy of cancer.gov.

A stage 1 melanoma has progressed a little farther into the epidermis, and possibly the dermis.

Stage 2 melanoma. Courtesy of cancer.gov.

Stage 2 melanoma. Courtesy of cancer.gov.

At stage 2, the melanoma has progressed even further into the dermis.

Stage 3 melanoma. Courtesy of cancer.gov.

Stage 3 melanoma. Courtesy of cancer.gov.

In stage 3, melanoma has spread into one or more nearby lymph nodes. It may have spread to other parts of the skin. However, it has not spread to other organs.

Stage 4 melanoma. Courtesy of cancer.gov.

Stage 4 melanoma. Courtesy of cancer.gov.

A stage 4 melanoma has spread to distant lymph nodes and may or may not include other organs. Stage 4 melanoma is very difficult to treat.

Melanoma treatment

As can be expected, treatment depends on each person’s specific melanoma. Here are some of the most current treatment options available.

Surgery is the best option for early stage melanomas and isolated metastatic melanomas. Surgeons usually refer to this type of surgery as wide excisions. This means they will try to remove not only the melanoma, but some of the skin around it in order to make sure the entire melanoma has been removed. Once a pathologist looks at the removed tissue, they will be able to determine if the entire melanoma has been removed.

Immunotherapy is a type of therapy mainly used for people who have a high risk of recurrence and metastases. According to the Melanoma Research Foundation, the following immunotherapies are approved by the FDA for the treatment of melanoma: Yervoy (ipilimumab), Keytruda (pembrolizumab), Opdivo (nivolumab), Interleukin-2 (IL-2) and Interferon alpha 2-b. The Cancer Research Institute also has more information about the FDA-approved drugs in addition to the newest information regarding melanoma-specific immunotherapy.

Clinical trials are usually recommended for melanomas at Stage Two and above. Clinical trials are also a good option for people whose melanomas are not good candidates for surgery or other traditional means. Clinical trials are the best way to find the newest and most promising therapies being tested by physicians and scientists.

Targeted therapy is a type of therapy that uses drugs or other substances to specifically target tumors without hurting normal cells.

Chemotherapy is effective with some types of cancer, but has shown to be of limited success treating melanoma.

Of course, the easiest and less-expensive way to treat melanoma is to prevent it from happening in the first place.

How to reduce melanoma in our population

Ban tanning beds. As a nation, we’re being diagnosed with skin cancer at a higher and higher rate in younger people. This is a developing public health crisis.

tanning-bed-dangerjpg

Tanning beds serve no benefit except to our own vanity. As long as tanning beds exist, people will continue developing skin cancer at higher rates. In my opinion, tanning beds should be declared a public health hazard and should be banned. I am not alone in that belief. 

Some states have existing laws, especially for minors, that limit tanning bed use.

Tanning Restrictions for Minors

I’m from Oklahoma–please notice that it is one of a batch of states in the middle of America that have no restrictions on tanning for minors. For more information on upcoming and past legislation in your state, please check out this page from the National Conference of State Legislators.

If you currently use a tanning bed, stop. If you allow your kids to use a tanning bed, stop. If you love and care about someone who is using a tanning bed, lovingly talk to them about everything you’ve learned while reading this post. Send them my way. Let me convince them that tanning beds are dangerous to their health.

Use sunscreen. Often. If you’re going to be outside for more than 20 minutes, put on sunscreen. Even on cloudy days! Don’t use sunscreen as an excuse to stay out in the sun for longer periods–that’s not what sunscreen is for. Be sure to use sunscreen that protects your skin from both ultraviolet A (UVA) and ultraviolet B (UVB) radiation. For more sunscreen tips, please see the American Melanoma Foundation’s website.

Wear protective clothing. Long sleeved shirts, hats, pants…anything that covers your skin. I know what you’re thinking, people from hot climates: NO. Don’t worry–there are options for you as well. Clothing companies such as Solumbra, Coolibar, and others provide garments with built-in sun protection that is breathable and easy to wear in the summer. For more tips on how to pick out the best sun-safe clothing, please see this page on the Skin Cancer Foundation’s website.

Check your skin often for abnormalities. Use the ABCDE method discussed earlier in this post about how to spot abnormal moles. If you see anything unusual or something that just doesn’t look right, see your dermatologist. Speaking of…

See a dermatologist at least once a year. It’s good to have a trained doctor take a look  in addition to checking your own skin. Making an appointment with a dermatologist was the first step in saving my life.


This blog post is personal for me. When I discussed my surgery and outcome, I heard from so many people from around the world. People shared their experiences with melanoma, which were both uplifting and absolutely heartbreaking. After reading this post, I hope I’ve conveyed the importance of taking care of your skin and scheduling yearly appointments with a dermatologist. It is honestly a matter of life or death.

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