Estimates are that p53 is mutated in 50% of all human cancers. If the gene that encodes p53 is mutated such that p53 is non-functional, what processes would be affected? CHECK ALL THAT APPLY

a) The ability to halt the cell cycle in response to DNA damage.

b) The ability to halt the cell cycle in response to the chromosomes not properly aligning on the metaphase plate.

c) The ability to repair DNA damage.

d) The ability to activate Cdks.

e) The ability to stimulate cell death processes if the cell is irreparably damaged.

The correct options are:

a) The ability to halt the cell cycle in response to DNA damage.

c) The ability to repair DNA damage.

e) The ability to stimulate cell death processes if the cell is irreparably damaged.

Explanation:

p53 gene has been called 'the guardian of the genome' because its prevents genome mutations which can bear to tumor formation. The main roles of p53 are:

DNA repair (option c) : it activates a ribonucleotide reductase which is involved in DNA repair when it is damaged.

Growth arrest (option a) : it avoids the cycle cell progression when a damage occur.

Apoptosis (option e) : it induces programmed cell death or apoptosis (because every cell must die eventually).

These processes are involved in prevention of tumor formation through activation/inhibition patways which in last instance prevent the replication of cells with a damaged/mutated genome.