It begins in certain cells in the skin called melanocytes. The skin is the body's largest organ. It has two main layers: the outer epidermis and the inner dermis. The epidermis is mostly made up of flat, scalelike cells called squamous cells. Round cells called basal cells lie under the squamous cells in the epidermis. Melanocytes are found throughout the lower part of the epidermis. They produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken.

Sometimes, clusters of melanocytes and surrounding tissue form benign (noncancerous) growths called moles. Melanoma occurs when these melanocytes (pigment cells) become malignant. Most pigment cells are in the skin; when melanoma starts in the skin, the disease is called cutaneous melanoma. Melanoma may also occur in the eye and is called ocular melanoma or intraocular melanoma. Sometimes melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found.

Melanoma can occur on any skin surface. In men, it is often found on the trunk (the area from the shoulders to the hips) or the head and neck. In women, melanoma often develops on the lower legs. Melanoma is rarer in black people and others with dark skin. When it does develop in dark-skinned people, it tends to occur under the fingernails or toenails, or on the palms or soles. The chance of developing melanoma increases with age, but this disease affects people of all age groups. Melanoma is one of the most common cancers in young adults.

When melanoma spreads it can spread to the lymph nodes and other parts of the body such as the liver, lungs, or brain. In such cases, the cancer cells in the new tumor are still melanoma cells, and the disease is called metastatic melanoma rather than liver, lung, or brain cancer.

A doctor should be seen if a person has 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. 'ABCD' can help you remember what to watch for (pictures at http://www.bu.edu/cohis/cancer/skin/skin.htm): 

• Asymmetry--The shape of one half does not match the other.

• Border--The edges are often ragged, notched, blurred, or irregular in outline; the pigment may spread into the surrounding skin.

• Color--The color is uneven. Shades of black, brown, and tan may be present. Areas of white, grey, red, pink, or blue also may be seen.

• Diameter--There is a change in size, usually an increase. Melanomas are usually larger than the eraser of a pencil (5 mm or 1/4 inch).

The traditional treatments for melanoma include surgery, radiation, chemotherapy, and more recently biologic therapy - using the body's immune system to fight cancer. 

Alternative approaches being tested include: Dendritic cell vaccines, antigen vaccines, herbal products like Hoxsey, Gerson therapy, and salves.  Also used are glycoalkaloids - one product that uses this is Skin Cancer Answer by Lane Labs. Clinical trials are also being done by Burzynski's Clinic using antineoplaston's for stage IV melanomas.