Why does uncontrolled proliferation occur even with DNA damage when a growth factor receptor, such as EGFR, has a mutation inhibiting its internalization upon ligand binding?

💡 Explanation

The cell cycle checkpoints halt progression when DNA is damaged, but with a mutated growth factor receptor that cannot internalize, the downstream signaling needed to activate those checkpoints is disrupted; because the receptor remains active at the cell surface, it continually signals proliferation rather than allowing for DNA repair or apoptosis, therefore uncontrolled proliferation occurs, rather than cell cycle arrest or programmed cell death.

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