It's also important to check your own skin, preferably once a month. You should be familiar with your pattern of moles, blemishes, freckles, and other marks on your skin so that you'll notice any changes.

Have a doctor look at any moles or spots on the skin that are changing in size, shape, or color. Any unusual sore, lump, blemish, marking, or change in the way the skin looks or feels may be a sign of skin cancer.

Know the difference in appearance between melanoma and an ordinary mole. Most people have moles, and most moles are harmless. But it is important to recognize changes in a mole that can suggest a melanoma may be developing.

The ABCD rule can help distinguish a normal mole from a melanoma:

• Asymmetry: One half of the mole does not match the other half.
• Border irregularity: The edges of the mole are ragged or notched.
• Color: The color of the mole is not the same. There may be differing shades of tan, brown, or black, and sometimes patches of red, blue, or white.
• Diameter: The mole is wider than six millimeters (about 1/4 inch). Any sudden or continuing increase in size should be of special concern.