Chapter 9, Problem 19RQ

A scientist notices that a cancer cell line fails to die when he adds an inducer of apoptosis to his culture of cells. Which hypothesis could explain why the cells fail to die?

1. The cells have a mutation that prevents the initiation of apoptosis signaling.
2. The cells have lost expression of the receptor for the apoptosis-inducing ligand.
3. The cells overexpress a growth factor pathway that inhibits apoptosis.
4. All of the above.