I’ll give a basic outline for you. During mitosis, one cell divides to become two separate cells. If the dna of a cell is damaged before or during mitosis, the cell can begin to reproduce uncontrollably. This creates many more damaged cells, usually resulting in a tumor. Everyone is at risk for cancer, but some are more likely than others. Some cell mutations can be passed through generations, but either way, Nikki is at risk for cancer.