Cancer is defined as abnormal cells that grow in an uncontrolled way, and in some cases, spread to other areas. Melanoma is the type of cancer when the abnormal cells are Melanocytes – they type of cells that make melanin in your skin. The reality is that every day, cells in your body, including some of your Melanocytes mutate and become abnormal. In fact, it is “normal” to have some abnormal cells in your body. However, normally the abnormal cells die, or your body, recognizing them as abnormal, kills them. In rare cases, however, they don’t die, your body doesn’t recognize them, or something cause many of them to mutate, and that’s when you get a Cancerous growth. Hence, things that either cause normal cells to turn abnormal, or prevent your body from fighting abnormal cells, are most often the causes of cancer. Below are a number of theories for what might cause melanoma specifically. In addition, you can read more about what causes melanoma to spread once you have it.
Exposure to Ultraviolet Light
The cause mainly attributed to melanoma is too much ultraviolet (UV) radiation reaching the skin. UV rays from the sun and other sources (such as tanning booths) can damage skin cells, causing the cells to grow abnormally. Most typically, the type of DNA damage caused by UV radiation to cells is called thymine dimerization, which if not repaired, can cause gene mutations on the cell, essentially making them “abnormal” cells.
Beyond increasing the risk of cancer, overexposure, and especially regular acute overexposure (i.e. getting sunburn a lot) can have a number of negative health consequences. It can repress the immune system, causes retinal diseases, and cause other health challenges.
On the other hand, not enough sun exposure can also be detrimental to your health. In fact, recent science actually suggests that moderate sun exposure actually offers more benefits than risks(3). The main reason is that your body naturally produces vitamin D when your skin is exposed to the sun. In fact, moderate sun exposure is often considered much more efficient for getting your body the vitamin D it needs, over taking vitamin D supplements. Additionally, and almost ironically, when your body gets the appropriate level of vitamin D it needs, such as that produced by moderate sun exposure, it can actually reduce the risk of some cancers by up to 60%(4).
How much sun exposure is “moderate” or enough? That’s a difficult question to answer, however, the following guidelines can help:
- Don’t get sunburned. Especially as a child, as significant childhood sunburn can greatly increase your risk of skin cancer later in life.
- Light skinned people can get the vitamin D they need with 5-30 minutes of sun exposure, twice a week, to the face, arms, legs or back without sunscreen. On a cloudy day, you would need to double this time. If you live in the Northern US (north of California, Massachusetts, Nebraska, Iowa), during the winter months, it is unlikely that you will get enough sun exposure to produce the appropriate amount of vitamin D, and hence should try vitamin D supplementation 5,6
- Dark skinned people need 10-20 times as much sun to produce the same level of vitamin D. Hence, dark skinned people should consider regular vitamin D supplementation
Impaired Immune System
Melanoma in particular, responds better than most other cancers to immune system stimulants. This is because your body’s immune system can be very helpful in fighting and killing melanoma cells. The corollary is that if you have an impaired immune system, your risk of developing melanoma goes up. There are a variety of theories about things that could impair your immune system, and cause you to become more susceptible to melanoma:
- Alcohol or drug abuse
- Diseases that repress the immune system, such as: Diabetes, AIDS, or autoimmune conditions
- Treatments that repress the immune system, such as: Chemotherapy or radiation, corticosteroids (such as long term prednisone)
- Removal of the spleen through surgery
- Difficult viruses that occupy the full resources of the immune system, and hence distract it from its normal cancer-fighting duties. One virus where research suggests a link between melanoma and the virus is cytomegalovirus (CMV), which is a form of herpes virus9
- High levels of toxicity, such as mercury or other heavy metals that can repress the immune system
- Exposure to carcinogens such as coal tar, the wood preservative creosote, arsenic compounds in pesticides and radium, petrochemicals, combustion products (such as car exhaust) 7,8
Genetics and Family History
It is generally understood that about 90% of melanomas are spontaneous. This means that they are the result of a specific cell mutation in a person (from too much UV radiation, for example). Hence, those 90% are not the result of genetics, and have nothing to do with whether melanoma “runs in the family.” However, about 10% of melanomas are the result of genetics. This is not because one generation passed melanoma itself down to another. Rather, what gets passed through genetics are gene mutations that can make you more susceptible to melanoma. In essence, if you have skin cancer in general, or melanoma specifically, in your family history, you should take extra precautions to avoid the main causes of melanoma listed above.
As a general rule, genetic risk for melanoma is suspected if two or more close relatives, such as a parent, sibling or child, is diagnosed with melanoma. There are several other factors as well which can indicate that melanoma is genetic and can “run in the family”, including:
- If the same person in that family develops more than one primary melanoma
- If the melanoma occurs early in a person’s lifetime, as most genetic melanomas develop in the mid-30s, which non-geneti c melanomas tend to develop later in life.
- If a person has multiple displatic nevi (which is the scientific term for “atypical mole”)There are some known genetic disorders that also raise a person’s risk level with melanoma. For example, a rare genetic disorder called xeroderma pigmentosum, which causes an extreme sensitivity to sunlight, can create a greatly increased risk of developing melanoma10