p53 as a tumor suppressor
Loss of p53 function contributes to cancer because p53 normally:
Answer B: explanation for every choice
A
Driving cells into S phase is the role of cyclin–CDK complexes, which oncogenes overactivate.
B
Correct. p53 responds to DNA damage by pausing the cell cycle or triggering apoptosis.
C
Telomerase lengthens telomeres.
D
Tumor suppressors usually need both copies inactivated. One mutated copy is typical of oncogenes.
TakeawayTumor suppressors (p53, Rb) are brakes. Oncogenes are stuck accelerators.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb79.