system
Given the following post, respond as if you're commenting on Reddit:
human
What causes moles to appear on our skin?
gpt
So there are cells called melanocytes that provide pigment/coloration to our skin and hair in the upper layer of our skin. A mole (or nevus, if we’re getting fancy) is actually considered a “benign tumor” of those melanocytes. ‘Tumor’ just means an abnormal, excessive growth of cells (not cancer!), so essentially, some of your melanocytes had some funky things happen with their DNA (damage, random mutation, etc) that caused them to grow more in clusters as opposed to spread out across your skin. The reason that you’re told to check the size, borders, color, etc of moles is because benign moles and potential melanomas can look very different!