The skin is the body's largest organ, weighing about 6 pounds. It protects us against sunlight, injury and infection. It helps regulate body temperature, stores water and fat, and produces vitamin D. The skin has two main layers: the outer epidermis and the inner dermis. 
The epidermis is mostly made up of fat, scalelike cells called squamous cells. Round cells called basal cells lie under the squamous cells in the epidermis. The lower part of he epidermis also contains melanocytes.
The dermis contains blood vessels, lymphatic vessels, hair follicles, and glands. Sme of these glands produce sweat, which helps regulate body temperature, and some produce sebum, an oily substance that helps keep the skin from drying out. Sweat and sebum reach the skin's surface through tiny openings called pores.
Healthy cells that make up the skin normally grow, divide, and replace themselves in an orderly way as the body needs them. This helps keep the skin in good repair.
Repeated exposure to sunlight, especially ultraviolet light, can cause a variety of cosmetic and medical problems in our skin. These include telangiectasia (red or purple “spider veins”), uneven pigmentation, lines and wrinkles, thinning of skin, loss of skin elasticity, and melanoma and other skin cancers. The damage our skin suffers from sunlight is cumulative and often gradual, so the effects appear as we age and worsen with time.
Skin cancer is a group of more than 100 diseases. It is the most common form of cancer in the United States. More that 500,000 new cases are reported each year-and the incidence is rising faster than any other type of cancer. While the skin cancers can be found on any part of the body, about 80 percent appear on the face, head, or neck, where they can be disfiguring as well as dangerous. Although each type of cancer differs from the others in many ways, every cancer is a disease of some of the body's cells.
Healthy cells that make up the body's tissues grow, divide, and replace themselves in an orderly way. This process keeps the body in good repair. Sometines, however, normal cells lose their ability to limit and direct growth. The divide too rapidly and grow without any order. Too much tissue is produced, and tumors begin to form. Tumors can be begin or maligmant.
· Benign tumors are not cancer. They do not spread to other parts of the body and are seldom a threat to life. Often, benign tumors can be removed by surgery, and they are not likely to return.
· Malignant tumors are cancer. They can invade and destroy nearby health tissue and organs. Cancer cells can also spread, or matastasize, to other parts of the body and form new tumors.
Who gets Skin Cancer... and Why?
The primary cause of skin cancer is ultraviolet radiation-most often from the sun, but also from artificial sources like sunlamps and tanning booths. In fact, researchers believe that our quest for the perfect tan, an increase in outdoor activities, and perhaps the thinning of the earth's protective ozone layer are behind the alarming rise we're now seeing in skin cancers.
Anyone can get skin cancer-no matter what your skin type, race, or age, no matter where you live or what you do. But your risk is greater if...
· Your skin is fair and freakles easily.
· You have light-colored hair and eyes.
· You have a large number of mole, or moles of unusual size or shape.
· You have a family history of skin cancer or a personal history of blistering sunburn.
· You spend a lot of time working or playing outdoors.
· You live closer to the equator, at a higher altitude, or in any place that gets intense, year round sunshine.
· You received therapeutic radiation treatments for adolescent acne.
Diagnosis and Treatment
Skin cancer is diagnosed by removing all or part of the growth and examining its cells under a microscope. It can be treated by a number of methods, depending on the type of cancer, its stage of growth, and its location on your body.
Most skin cancers are removed surgically, by a plastic surgeon or a dermatologist. If the cancer is small, the procedure can be done quickly and easily, in an outpatient facility or the physician's office, using local anesthesia. The procedure may be a simple excision, which usually leaves a thin, barely visible scar. Or curettage and desiccation may be performed. In this procedure the cancer is scraped out with a special instrument and the area is treated with an electric current to control bleeding and kill any remaining cancer cells. This leaves a slightly larger, white scar. In either case, the risk of the surgery are low.
If the cancer is large, however, or if it has spread to the lymph glands or elsewhere in the body, major surgery may be required. Other possible treatments for skin cancer include cryosurgery (freezing the cancer cells), radiation theraphy (using x-rays), and Mohs surgery, a special procedure in which the cancer is shaved off one layer at a time. (Mohs surgery is performed only by specially trained physicians and often requires a reconstructive procedure as a follow-up.)
Preventing a Recurrence
After you've been treated for skin cancer, your doctor should schedule regular follow-up visits to make sure the cancer hasn't recurred.
Your physician, however, can't prevent a recurrence. It's up to you to reduce your risks by changing old habits and developing new ones. (These preventative measures apply to people who have not had skin cancer as well.)
· Avoid prolonged exposure to the sun, especially between 10 a.m. and 2 p.m. and during the sumer months. Remember, ultraviolet rays pass right through water and clouds, and reflect off sand and snow.
· When you do go out for an extended period of time, wear protective clothing such as wide-brimmed hats and long sleeves.
· On any exposed skin, use a sunscreen with an SPF (sun protection factor) of at least 15. Apply it liberally, about an hour before you go out, and reapply it frequently, especially after you've been swinning or sweating.
· Finally, examine your skin regulary. If you find anything suspicious, consult a plastic surgeon or a dermatologist as soon as possible.