Most skin cancers fall into three classes, basal cell carcinomas. Squamous cell carcinomas, and melanomas. In the US there were 500,000 cases of the first, 100,000 of the second, and 27,600 of the third in 1990. [Wayne] More than 90% of the skin carcinomas in the US are attributed to UV-B exposure: their frequency varies sharply with latitude, just as UV-B does. The mechanism by which UV-B induces carcinomas has been identified - the pyrimidine bases in the DNA molecule form dimers when they absorb UV-B radiation. This causes transcription errors when the DNA replicates, giving rise to genetic mutations.[Taylor] [Tevini] [Young et al.] [Leffell and Brash]. Fortunately, nonmelanoma skin cancers are relatively easy to treat if detected in time, and are rarely fatal. Fair-skinned people of North European ancestry are particularly susceptible; the highest rates in the world are found in Queensland, a northerly province of Australia, where a population of largely English and Irish extraction is exposed to very high natural UV radiation levels. ( From http://www.faqs.org/faqs/ozone-depletion/uv/)

Types of Skin Cancer

Melanoma (sometimes called cutaneous melanoma or malignant melanoma)

According to the National Cancer Institute-Melanoma is a disease of the skin in which cancer (malignant) cells are found in the cells that color the skin (melanocytes). Melanoma usually occurs in adults, but it may occasionally be found in children and adolescents. Your skin protects your body against heat, light, infection, and injury.

Like most cancers, melanoma is best treated when it is found (diagnosed) early. Melanoma can spread (metastasize) quickly to other parts of the body through the lymph system or through the blood. (Lymph nodes are small, bean-shaped structures that are found throughout the body; they produce and store infection-fighting cells.) You should see your doctor if you have any of the following warning signs of melanoma: change in the size, shape, or color of a mole; oozing or bleeding from a mole; or a mole that feels itchy, hard, lumpy, swollen, or tender to the touch. Melanoma can also appear on the body as a new mole. Men most often get melanoma on the trunk (the area of the body between the shoulders and hips) or on the head or neck; women most often get melanoma on the arms and legs.

Malignant melanoma is much more dangerous, but its connection with UV exposure is not well understood. [van der Leun and de Gruijl] [Ley]. There seems to a correlation between melanomas and brief, intense exposures to UV (long before the cancer appears.) Melanoma incidence is correlated with latitude, with twice as many deaths (relative to state population) in Florida or Texas as in Wisconsin or Montana, [Wayne] but this correlation does not necessarily imply a causal relationship. There is some evidence that UV-A, which is not absorbed by ozone, may be involved. ( From http://www.faqs.org/faqs/ozone-depletion/uv/)

Basal Cell & Squamous Cell
There are several types of cancer that start in the skin. The most common are basal cell cancer and squamous cell cancer.

Skin cancer is more common in people with light colored skin who have spent a lot of time in the sunlight. Skin cancer can occur anywhere on your body, but it is most common in places that have been exposed to more sunlight, such as your face, neck, hands, and arms.

Skin cancer can look many different ways. The most common sign of skin cancer is a change on the skin, such as a growth or a sore that won't heal. Sometime there may be a small lump. This lump can be smooth, shiny and waxy looking, or it can be red or reddish brown. Skin cancer may also appear as a flat red spot that is rough or scaly. Not ail changes in your skin are cancer, but you should see your doctor if you notice changes in your skin.

Skin Cancer & You

It is estimated that 1 out of 7 people in the United States will develop some form of this cancer during their lifetime. One serious sunburn can increase the risk by as much as 50%.

The good news is skin cancer is preventable and curable, if detected early. Several studies point to early prevention being the best, saying that preventing sun-burns as children is one of the greatest protections against skin cancer. Many of us are familiar with the PSA reminding us of what to do while we are out in the sun: Slip, slop, slap. Slip on a shirt, slop on sunscreen and slap on a hat. This campaign illustrates an important point in protection against skin cancer; it's important to use multiple methods/layers in order to be fully protected from the sun.

Experts agree that anytime you are in the sun for a prolonged period of time (longer than 15 minutes), you should cover up any exposed skin. This includes wearing a wide brimmed hat (darker colors may provide more protection) and wrap around sunglasses. You should always use sunscreen that is at least SPF 15. Don't forget to use it on your face, ears, neck, back of hands and tops of feet. Always use lip balm with SPF as well. Sunscreen should be applied at least two hours before going out and reapplied after swimming or sweating in order to be effective. Even if you are in the shade, sunscreen is needed. The sun's rays can be reflected off of anything and the shade isn't a guarantee of safety. It can also reflect off of sand, snow and water, requiring sunscreen during the entire year and with any outdoor activity. Avoid the sun during the "peak" hours of the day; 10 am to 3 or 4 pm.

Dermatologists recommend everyone get to know their skin. Do monthly self skin examinations and have your doctor do a thorough exam yearly and note any changes. If skin cancer is found and treated early, the cure rate can reach close to 100 percent. However, the best cure for skin cancer is prevention. Enjoy the sun sensibly!

Read more about protecting your skin- HERE

ABCs to protect skin:

A- Away; stay away from the sun during the day
B- Block; use sun block of at least SPF 15
C- Cover up; cover all exposed skin, use sunglasses
S- Speak out; teach others about protection

May is skin cancer awareness month. You can order materials for schools or personal use to raise awareness from web sites such as skincancer.org, cancer.gov and cdc.gov.