Could The Mole Under The Fingernail Be Cancerous?

My 3 year old granddaughter has a mole under her small finger fingernail; it appeared when she was 1. Doctors said to watch it - my daughter saw a dermatologist when she was 2 and again today now that she is 3. My daughter and son-in-law asked that it be biopsied, and the results will be in within 2 weeks. What are the chances that this mole could be cancerous? My daughter is 38 weeks pregnant, and a basket case with worry. What do you think should be done?