Do shorter telomeres cause cancer?
In 2011, two meta-analysis9,10 pooling more than 20 studies reported that the short telomeres were associated with increased cancer risk. They also found particularly strong evidence for bladder, esophageal, gastric, and renal cancers, but the study numbers were limited for each cancer type.
How telomeres affect cancer cells?
Cancer cells often avoid senescence or cell death by maintaining their telomeres despite repeated cell divisions. This is possible because the cancer cells activate an enzyme called telomerase, which adds genetic units onto the telomeres to prevent them from shortening to the point of causing senescence or cell death.
What is the relationship between the length of telomeres telomerase and cancer?
Telomeres maintain genomic integrity in normal cells, and their progressive shortening during successive cell divisions induces chromosomal instability. In the large majority of cancer cells, telomere length is maintained by telomerase.
Can cancer cells regenerate telomeres?
With each cell division, telomeres shorten until eventually they become too short to protect the chromosomes and the cell dies. Cancers become immortal by reversing the normal telomere shortening process and instead lengthen their telomeres.
Is it good to have long telomeres?
Critically shortened telomeres lose their ability to protect chromosome ends, inducing cell cycle arrest and senescence. While the consequences and cellular response to short telomeres are frequently explored, long telomeres also pose problems and cells have evolved mechanisms to shorten over-elongated telomeres.
How does telomerase cause cancer?
Telomerase activity is closely related to the life stages of the body. The enzyme is active during embryonic development. Cancer cells are characterized by high telomerase activity, which enables cells to divide indefinitely. Telomerase is active in 85–95% of cancers (3,4).
Why does telomerase cause cancer?
It is believed that cancer occurs because a genetic mutation can trigger the production of an enzyme, known as telomerase, which prevents telomeres from shortening. While every cell in the body has the genetic coding to produce telomerase, only certain cells actually need it.
How does fully active telomerase contribute to cancer?
Increased telomerase expression produces vulnerability of cancer cells, distinguishing them from normal cells in the body, although normal cells do also have some active telomerase. Recent studies also suggest that telomerase is implicated in tumor progression in unexpected ways.
Are telomeres the key to aging and cancer?
Telomeres affect how our cells age. Once they lose a certain number of bases and become too short, the cell can no longer divide and be replicated. This inactivity or senescence leads to cell death (apoptosis) and the shortening of telomeres is associated with aging, cancer and an increased likelihood of death.