Moles on our skin are pretty common. Lots of people have them. Sometimes they’re cute, like an Iggy Azalea beauty mark.

Moles and melanomas are skin tumors, both caused by cells called melanocytes [muh-la-nuh-sites]. Moles are generally harmless, whereas melanomas can be deadly if untreated.

Scientists from the Huntsman Cancer Institute and the University of Utah have published a new study that delves into how moles and melanomas form and why moles can turn into cancer.

Changes to the DNA sequence of melanocytes, called BRAF [braff] gene mutations, are found in more than 75% of moles. The same change is found in about half of all melanomas.

Researchers used to believe that when melanocytes only had the BRAF mutation, the cell stopped dividing, resulting in a mole. And when other mutations were in the mix, it would divide uncontrollably and become cancerous.

The new study shows that’s not the case.

The scientists used techniques — including one called digital holographic cytometry [sai-taa-muh-tree] — to scrutinize the differences between moles and melanomas.

The researchers found that the cells that become melanoma don’t  necessarily have these extra mutations. But they are affected by “environmental signaling,” which happens when cells receive signals from the environment in the skin around them, telling them how to behave, and whether to divide uncontrollably or not at all.

That means scientists might be able to find ways to beat melanoma by altering its environment, potentially targeting topical agents that can thwart melanoma or at least slow it down.

So while you may never come to love your moles, at least you wouldn’t have to fear them.