|
 |
Chromosome ends linked to smoking-related cancers
Source: (cancerfacts.com)
Wednesday, August 20, 2003
HOUSTON – Aug. 20, 2003 – People whose chromosomes contain short end-pieces, called telomeres, as measured in white blood cells, appear to be at an increased risk for smoking-related cancers, according to a new study.
Chromosomes are the tightly bundled x- and y-shaped structures in the cell nucleus that contain all the DNA during certain phases of the cell cycle. Like the aglet of a shoelace, telomeres form the ends of the chromosomes and in part serve to protect them from "fraying" and mutating.
The research team led by Dr. Xifeng Wu, of the University of Texas M. D. Anderson Cancer Center, examined the telomeres in white blood cells and found that compared with people with longer telomeres, people with shorter telomeres had a higher risk for bladder, head and neck, lung, and renal cell cancers--cancers that are associated with cigarette smoking. They published their findings in the Aug. 20 issue of the Journal of the National Cancer Institute.
"Future research should focus on the associations of telomere dynamics, cell cycle checkpoints, apoptosis, the activation of telomerase, and DNA repair capacity, ultimately, with the goal of enhancing our ability to identify high-risk subgroups," the researchers wrote.
Although telomere shortening is associated with aging, earlier studies have shown that telomere length can vary considerably among people of the same age. That observation raised the possibility that individuals with shorter telomeres are at an increased risk of cancer, as short telomeres have been associated with increased risk of intestinal and epithelial cancers.
To examine the association between telomere length and cancer risk, Wu and colleagues measured telomere length in the circulating white blood cells of patients participating in four ongoing studies of head and neck, bladder, lung, and renal cell cancers.
They found that patients with these cancers had statistically significantly shorter telomeres than patients without cancer and that increased cancer risk was associated with progressively shorter telomeres.
In addition, factors such as age, gender, and smoking status appeared to influence the effect that short telomeres had on cancer risk. People who smoked and had short telomeres had a substantially greater risk for tobacco-related cancers than people who never smoked and had short telomeres or people who smoked but had longer telomeres.
The researchers noted that they measured telomere length in a normal white blood cells, not in cancer cells, and that cancer cells do have different telomere dynamics.
In an accompanying editorial, Drs. Kwok-Kin Wong, and Ronald A. DePinho, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston, point out that many studies have started to explore the usefulness of determining telomere length in more accessible white blood cells rather than in diseased tissue.
They say that the current study "raises a number of intriguing possibilities that relate to how telomeres influence tumorigenesis (generation of tumors) in the aged." While, they caution that it is too early to link telomere length in white blood cells with the risk of cancer. They say that the new findings warrant a large prospective epidemiologic study designed to determine whether telomere length, measured in early life or at least before the onset of cancer, is associated with the risk of developing cancer.
Copyright © 2001, 2002, 2003 NexCura, Inc. All rights reserved. Republication or redistribution of cancerfacts.com content, including by framing or similar means, is expressly prohibited without the prior written consent of NexCura. NexCura® is a registered trademark and cancerfacts.com™ is a trademark of NexCura, Inc. or its affiliates. Copyright © 2001, 2002, 2003. All rights reserved. This information is for educational purposes only.
|
|
|
|
|
|
