The ability of a normal cell to become a cancer cell can occur via a variety of mechanisms. Which one of the following best describes such a mechanism?
A.Tumors arise via the acquisition of the ability to metabolize glucose at a faster rate than noncancer cells.
B.Clonal expansion allows for a cell with a single mutation to become a cancer cell.
C.Mutations in proto-oncogenes can lead to uncontrolled cell growth.
D.Virtually all tumors arise via recombination events, leading to the formation of unusual and novel genes.
E.Normal cellular oncogenes are mutated to proto-oncogenes, which leads to uncontrolled cellular proliferation.