Telomere length may be marker for aggressive prostate cancer

Men with short-ended chromosomes in the immune cells in their blood appear to be at increased risk for aggressive prostate cancer compared with men with long-ended chromosomes, according to findings from a recent study.

The study, presented at an American Association for Cancer Research (AACR) International Conference in National Harbor, MD, suggests that the length of telomeres in blood leukocytes could be a biomarker of risk for aggressive prostate cancer.

“In research that we published earlier this year in the AACR journal Cancer Discovery (2013; 3:1130-41), we found that men with prostate cancer who had high variability in the length of telomeres from one prostate cancer cell to another and shorter telomere length in prostate cancer-associated stromal cells were substantially more likely to develop metastases or die of their disease compared with men with prostate cancer harboring neither of these characteristics,” explained co-author Elizabeth A. Platz, ScD, MPH, of the James Buchanan Brady Urological Institute at Johns Hopkins School of Medicine, Baltimore.

For the current study, Dr. Platz and her colleagues wanted to look at a more easily accessible tissue-the blood-and look at earlier time points to determine whether telomere length could predict a man’s future risk of prostate cancer.

They analyzed DNA from leukocytes isolated from blood samples provided from 1993 to 1995 by men who enrolled in Harvard’s Health Professionals Follow-up Study. They studied 441 men who later developed prostate cancer, with a mean time from blood draw to diagnosis of 3 years, and 421 men who did not develop prostate cancer during follow-up.

Relative telomere length was measured in all study participants’ blood leukocytes by quantitative polymerase chain reaction and categorized into tertiles based on the distribution of telomere length in the men who did not develop prostate cancer.

The authors found that among the men who developed prostate cancer, those with the shortest telomeres in their leukocytes at blood draw-those with telomere lengths in the bottom two tertiles-were more than twice as likely to have developed aggressive prostate cancer compared with those men who had the longest telomeres-telomere lengths in the top tertile.

When the authors narrowed their analysis to men who smoked or had smoked in the past, they found that those with the shortest telomeres in their blood leukocytes were more than four times as likely to have gone on to develop aggressive prostate cancer.

“We don’t yet know why having short telomeres in blood leukocytes seems to be associated with risk of aggressive prostate cancer. It may tell us about a person’s exposure to factors that increase their risk of prostate cancer, or it may be an indication of an inherent inability to maintain telomere length, which could put them at increased risk for this disease. If so, it might be that measuring telomere length in blood leukocytes could even predict risk of many different forms of cancer,” Dr. Platz said.

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