It can often be called as Carcinogenesis or tumorigenesis which means cancer creation. It is a process by which cancer cells are transformed by normal cells and is characterized by a progression of changes at genetic and epigenetic level.Carcinogenesis is caused by mutation of the genetic material of normal cells and finally results in uncontrolled cell division which leads to benign tumors.These tumors do not spread to other parts of the body and they are rarely life threatening.