I would say that mitosis happens with the cells when you have cancer. Cancer cells multiply and keep multiplying till they outnumber the good cells, and generally when that happens you die. Since cancer is caused by a gene mutation, that can allow things to happen, such as rapid cell growth, uncontrollable cell growth, and can cause mistakes when repairing DNA cells. However, I do not know if this is the right answer. This is based just off of my knowledge and understanding on the topic