Gene
Finding Will Help Doctors Predict Prostate Cancer Risk
Researchers report that a variation in a portion of DNA
strongly predicts prostate cancer risk, according to a study in Nature
Genetics.
In addition, this common variation may be responsible for
up to 20 percent of prostate cancer cases in Caucasian men in the US.
DNA is short for deoxyribonucleic acid, which is the genetic
material determining the makeup of all living cells.
The research was conducted by investigators from the National
Cancer Institute (NCI) and partners in the Cancer
Genetic Markers of Susceptibility (CGEMS) initiative.
Prostate cancer is the third leading cause of cancer-related
death in men, yet very little is known about its origins, scientists say.
In 2007 in the US, there will be an estimated 219,000 new
prostate cancer cases and an estimated 27,000 deaths.
CGEMS researchers are scanning
the entire human genome to identify common, inherited gene mutations that increase
the risks for breast and prostate cancers.
"Discovery of this common variation is very exciting," says
Dr. John E. Niederhuber, director of the NCI.
"Building on this finding we may be able to identify men
at highest risk for prostate cancer, diagnose the disease earlier, and hopefully
prevent it all together," says Dr. Niederhuber.
"One of the next steps is to understand the mechanism by
which this genetic variation exerts its effect on cancer risk," he notes.
This gene variation was discovered on chromosome 8.
Humans normally have 46 chromosomes in each cell, divided
into 23 pairs. Two copies of chromosome 8, one inherited from each parent,
form one of the pairs.
Chromosome 8 spans about 146 million base pairs (the chemicals
that comprise DNA), represents about 5 percent of the total DNA in cells, and
contains an estimated 700 to 1,100 genes.
“We
now have two significant regions in the same general area that convey risk
for
prostate cancer, says Dr. Meredith Yeager, lead author
on the study.
One location under study could be responsible for about
seven percent of prostate cancer cases in Caucasian men of northern European
descent.
The two genetic regions together could account for as much
as one quarter of prostate cancer cases in Caucasian men.
“CGEMS allows
us to look systematically across the entire human genome and search for common
genetic
variations that confer risk for prostate cancer, a very common and very complex
disease,” says Dr. Stephen Chanock, director of the NCI Core
Genotyping Facility in the Advanced Technology Center.
Dr. Gilles Thomas, a lead scientist at CGEMS,
says that identification of new regions furthers efforts to uncover the genetic
basis of prostate cancer, which may eventually lead to more insights into cancer
causes in general.
Currently, scientists are collecting similar data on breast
cancer, the second leading cause of cancer-related deaths in women in the US.
The CGEMS database will soon
contain close to 2.5 billion genotypes, allowing researchers to identify genetic
risk factors for breast and prostate cancers.
By comprehensively surveying for common genetic variations
and following-up on promising findings, researchers hope to identify and verify
associations that increase or decrease the risk of these cancers.
Always consult your physician for more information.
|
