JAMA: Length of telomeres associated with cancer risk
Shorter length of leukocyte telomeres–chromosome markers of biological aging–are associated with an increased risk of cancer and death from cancer, according to a study in the July 7 issue of Journal of the American Medical Association.

A leukocyte is a type of blood cell, and telomeres are a structure at the end of a chromosome involved in the replication and stability of the chromosome. Genetic factors and environmental stressors can shorten the length of the telomere, and telomere length has been considered to be an emerging marker of biological age.

Peter Willeit, MD, from the Innsbruck Medical University in Innsbruck, Austria, and colleagues conducted a study to assess the association between leukocyte telomere length and risk of both new-onset cancer and cancer death.

Leukocyte telomere length was measured by quantitative polymerase chain reaction in 787 participants, free of cancer in 1995, and part of the prospective, population-based Bruneck Study in Italy. The primary outcomes analyzed included the incidence of new cancer and cancer mortality over a follow-up period of 10 years (1995-2005).

During follow-up, a total of 11.7 percent of participants developed cancer, according to the researchers. Analysis indicated that short telomere length at the beginning of the study was associated with new cancer independent of standard cancer risk factors.

Compared with participants in the longest telomere length group with cancer incidence rates at 5.1 per 1,000 person-years, participants in the middle length group had incidence rates at 14.2 per 1,000 person-years, and those in the shortest length group had incidence rates at 22.5 per 1,000 person-years.

Cancer incidence rates were inversely related to telomere length, with participants in the group with the shortest telomere length having the highest rate of cancer, concluded Willeit and colleagues.

Short telomere length was also associated with a higher rate of death from cancer. “Of note, telomere length was preferentially associated with individual cancers characterized by a high fatality rate such as gastric, lung, and ovarian cancer, but less so with tumors linked to better prognosis,” the authors wrote. They added that telomere length had a similar predictive value for cancer in both men and women and in various age groups.