Mr. Smith has found a lump under his arm. He goes to his doctor, and the doctor confirms that the lump is cancer. How are cancerous cells different from normal cells?

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A.
carcinogens change cancer cells to normal cells
B.
cancer cells are found in the lymph; normal cells are not
C.
the growth-regulating genes of cancer cells have mutated
D.
cancer cells occur in adults but not in children