As any respectable crossword puzzle fan knows, the little tip at the end of a shoelace is called an aglet. Similarly, as genetic scientists know, there are little tips at the ends of every chromosome. They're called "telomeres," and like aglets, they keep strings from fraying, although they're a bit more complicated than the simple plastic shoelace covers; telomeres are made up of long stretches of specialized DNA. "Unfortunately," says scientist Alan Meeker, Ph.D., "every time a cell divides, a portion of the telomere's DNA is lost. Thus, as we age, our telomeres progressively get shorter."
" Every time a cell divides, a
portion of the telomere's
DNA is lost. Thus, as we age,
our telomeres progressively
From previous work, Meeker and colleagues including Don Coffey have come to believe that this shortening of telomeres is an important contributing factor to the development of prostate cancer. Every time the buffer between a chromosome and the outside world shrinks, it is that much more vulnerable to injury.
As part of nature's luck of the draw — the genetic blessings and hindrances all of us are born with, through no fault or virtue of our own — some men are fortunate enough to be born with long telomeres; others are born with shorter ones. "In fact, variations in telomere length are inherited," says Meeker. This made him wonder: Do men who inherit short telomeres have a higher risk of developing prostate cancer?
In a recent study, he and colleagues used a simple blood test to find out. They measured telomere length in 127 people from 17 families who are part of the Johns Hopkins Hereditary Prostate Cancer family registry. "We found that in 10 of these families, the average telomere lengths were shorter in men with prostate cancer when compared to their unaffected family members," says Meeker, and this finding has exciting implications that may help in early diagnosis. "We believe that measuring telomere length, with a blood test, in men with a strong family history may help determine their risk of developing prostate cancer." Men found to be at risk, he adds, could receive targeted interventions aimed at trying to slow down the rate of telomere loss, or at preventing further growth of prostate cells.