What is Melanoma?

Melanoma is a cancer of pigment producing cells called melanocytes. Most melanomas originate from the skin, though they can also arise from other parts of the body containing
melanocytes, including the eyes, brain or spinal cord, or mucous membranes. Some melanomas are first detected when they spread to other parts of the body, without a documented primary tumor.
    
Melanoma of the skin is one of the most common cancers in the United States – among the top 10 causes of new cancer cases. While the overall five-year survival rate for people diagnosed with melanoma is high at 92 percent compared to 66 percent for all other cancers, the survival rate decreases dramatically once melanoma spreads to other parts of the body. Very early stage (localized, Stage 0 or I) melanoma is greater than 90 percent curable with surgery, while patients with disseminated Stage IV melanoma have a median life expectancy of less than one year.
    
The ability to spread widely to other parts of the body is a unique characteristic of melanoma that the other more common skin cancers, basal cell carcinoma and squamous cell carcinoma, do not possess. This characteristic makes melanoma the deadliest of all skin cancers: it accounts for only four percent of skin cancers, but 80 percent of skin cancer-related deaths.
 
Source: melanomaresearchalliance.org