Tumorigenesis can be viewed as a process of cellular evolution in which individual
preneoplastic or tumor cells acquire mutations that increase proliferative capacity and thus
confer a selective advantage. This evolutionary process permits tumor cells to escape the
restrictions that limit growth of normal cells, such as the restraints imposed by the immune
system or adverse metabolic conditions. The iterative process of mutations and selections
underlying tumor evolution may be dependent on the ability of cells to mutate. Normal cells …