Melanoma is the most dangerous form of skin cancer, and it comes in many different shapes and sizes.

We recently received this question from a concerned viewer:

Dr. Manny,
My dad has a mole that I keep telling him to get checked out. It looks like it has changed color over the years. How can I tell if it's melanoma?

The best way to tell if you have skin cancer is by going to the doctor to have your skin checked.

Melanoma can develop anywhere on your body, and while identifying it should be left to medical professionals, remembering your ABCs can help you detect a problem.

Asymmetry: Look for moles or freckles with two very different looking halves to them.

Border Irregularity: Notched, scalloped or blurred edges can be characteristics of melanoma.

Color: If the color of a mole is not uniform and different shades can be seen, get it checked out.

Diameter: If it’s bigger than 1/4 inch or if it grows in size, it should be evaluated.

Evolution: Any change in size, shape or symptoms – like itching, tenderness or bleeding – is cause for immediate medical attention.

Prevention is the best medicine, so see your doctor at least once a year for a skin evaluation and make sure you wear sunscreen year-round.

Do you have a health question? We want to hear from you! Send it to DrManny@FoxNews.com.