Going back to the definition of cancer, uncontrolled cell growth, one of the main functions of this is being able to replicate at a high rate and continue to replicate. One main contributor to the replicative power of cancer cells is a molecule called a telomere.
You may have heard of telomeres before. They are widely talked about in the news. These are repeating DNA sequences at the end of a chromosome. To review, DNA is wound up into tight packages called chromosomes during replication. These telomeres act as a binding at the end of the chromosome so it does not unwind. A common analogy is a shoe lace cap at the end of a shoe lace.
Here are some proteins associated with telomeres.
Telomerase. Telomerase is an enzyme (a protein that speeds up chemical reactions) that builds telomeres. If telomeres get damaged, telomerase adds to them for rebuilding.
hTERT. hTERT is the part of telomerase that acts to grow the repeating sequence of the telomere.
Cells undergo death when they have had too many replications. One of the main contributors to this death is a shortened telomere. After each replication, the telomere shortens.
But what happens if the telomeres do not shorten after each replication? That is how some cancer cells maintain their replicative-ness. The cancer can express more hTERT, which is the component of telomerase that rebuilds telomeres. So, the cell may not die by the shortening telomere method because the telomeres never shorten!
Topics in Cancer Biology 