Determining if a mole on your skin is a harmless addition or a dangerous invasion can be as simple as A-B-C-D, according to a new video by Dr. Christian Jessen. Dr. Jessen reveals how a four-step process can easily determine how risky a new mole may be in terms of its potential for cancer. Jessen’s practice is based on the acronym A-B-C-D, breaking down four characteristics of a mole that must be checked on:

A stands for asymmetry. If the mole’s shape is different on one side than the other, it’s worth getting checked out.

B stands for border. A mole that has “jagged” edges could be a sign of trouble.

C stands for color. The mole should be a uniform color. If it’s not, ask a doctor to take a look.

D stands for diameter. The smaller the mole, the less likely it’s a sign of trouble. However if it’s growing in size or is greater than 6mm in length, best get it checked out.

Another doctor says that flat moles are usually more likely to turn cancerous than those raised above the skin, according to an article in the Milwaukee Community Journal. Dermatologist Neal Schultz says, “It’s usually the flat moles that get into trouble. Raised moles are intradermal moles, or compound moles, and they have a much lower rate of malignant degeneration. Flat moles are where most of the cases of melanoma come from.”