All types of cancer are caused by the genetic mutations and damage due to these mutations of our nucleic acids-DNA. But in order to address cancer cases in individuals, there are many other reasons which lead to cancer in a human being. For example, one of the major reasons for cancer is genetic inheritance; traits transferred from one generation to another.
Other causes are of external nature which is linked to factors like environment and food we eat.
In the United States, cancer is ranked as the second most fatal disease which causes death of individuals. The nature of this disease includes mutations and overproduction of certain cells i.e. tumors that act like toxic intruders to the human body and leading it to destruction.
It is true that there are many causes of cancer which are beyond human control like genetic mutations caused by inheritance or the changes which the human body undergoes in a lifetime. But there are still a large number of reasons which can be dealt with by our efforts and precautions to reduce the chances of cancer, just like avoiding carcinogens from entering into our body and eating stuff which is light and healthy.