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press release (HT: href="http://www.medgadget.com/archives/2007/07/got_moles_they_might_be_good_for_you.html">medGadget)
from King's College tips us off to an article in the journal, href="http://cebp.aacrjournals.org/">Cancer
Epidemiology Biomarkers & Prevention.
This is something that news sites picked up on.
Specifically, the authors reported a relationship between the
number of moles a person has, and the length of their href="http://en.wikipedia.org/wiki/Telomere" rel="tag">telomeres.
Telomere shortening is thought to be an href="http://www.kfshrc.edu.sa/annals/186/98-246ed.html">indicator
Size and Number Are Associated with Telomere Length and Represent
Potential Markers of a Decreased Senescence In vivo
Veronique Bataille, Bernet S. Kato, Mario Falchi, Jeffrey Gardner,
Masayuki Kimura, Marko Lens, Ursula Perks, Ana M. Valdes, Dot C.
Bennett, Abraham Aviv and Tim D. Spector
Cancer Epidemiology Biomarkers & Prevention
16, 1499-1502, July 1, 2007
counts represent one of the strongest risk
factors for melanoma. They appear in childhood and adolescence and
involute from middle age onwards. Recent evidence has shown that nevus
cells undergo oncogene-induced senescence involving the
p16/retinoblastoma pathway. However, telomere length also influences
senescence in proliferative somatic cells and varies between
individuals. This study explores whether telomere length measured in
white cells is associated with nevus count and size in 1,897 Caucasian
women ages 18 to 79 years. Total body nevus counts were positively
correlated with white cell telomere length (mean, 7.09 kbp; range,
5.09-9.37) after adjustment for age (P = 0.0001). Age-adjusted telomere
length was also associated with nevus count for nevi above 5 mm in
diameter (P = 0.04). Subjects in the top category for nevus count had
an average age-adjusted telomere length 150 bp longer than those in the
lowest category. The positive correlation between white cell telomere
length and nevi number and size may reflect an increased replicative
potential (reduced senescence) in individuals with longer telomeres,
which may not be melanocyte specific. Understanding mechanisms
influencing the induction and involution of nevi will not only help in
understanding the pathophysiology of melanoma but should also shed
light on the complex relationship between aging and cancer. (Cancer
Epidemiol Biomarkers Prev 2007;16(7):1499–502)
Moles usually appear in when a person is young,
then become smaller and disappear with age.
The study suggests that the longer telomeres may cause the moles to
persist longer, because the cells retain their ability to replicate.
One way to look at it would be to say that as the cells in the mole
grow old and die, cells in the rest of your body are growing old and
dying. If the moles last longer, then other body tissues are
are specialized DNA-protein complexes that cap the end of eukaryotic
chromosomes and are essential for maintaining genome stability and
integrity... Shortening of telomeres occurs naturally with successive
divisions in somatic cells, whereas in the germ-line and most cancer
cells, high telomerase activity allows cells to maintain long telomeres
and avoid senescence.
The authors of the study are careful to avoid drawing any broad
conclusions from this, in part because they only studied women, and all
of them were from the UK. They add that some studies have
shown a relationship between telomere shortening and cancer, while
others have not.