Do you have a lot of moles on your body? If so, you're not alone. According to WebMD, most people will have 10 to 40 moles by adulthood. Many people are embarrassed by their unsightliness and opt to have them removed. However, there's sometimes a different, more important reason, some people have mole removal. Certain moles can be cancerous. Here's what you need to know about moles and how to spot signs that they might be skin cancer.