Researchers at the Case Western Reserve University have taken a major step forward in the fight against cancer, by identifying the genetic components of colorectal cancer (CRC.)
The study, entitled, "Identification of Susceptibility
Genes for Cancer in a Genome-wide Scan: Results from the Colon Neoplasia
Sibling Study" is the first large linkage work of families with CRC and colon
polyps in the country.
The researchers said that their study is a step
towards the future of genetic testing for the third most commonly diagnosed
cancer in Americans.
Because only five percent of CRC cases are due to
known gene defects, this NIH-funded study is designed to spot the remaining
CRC-related susceptibility genes.
For the study, the team built on a previous study,
which identified a specific region on chromosome 9q that harbors a CRC
Upon review of a whole genome scan of all chromosome
pairs in 194 families, the researchers were able to identify additional CRC
gene regions on chromosomes 1p, 15q, and 17p.
While the overall Case Western Reserve University
School of Medicine study looked at families with colon cancer and colon polyps,
the study also analyzed families with different clusters of cancer, such as CRC
with multiple polyps and CRC with breast cancer.
These different phenotypes appeared to link to different chromosomal
regions, which the study teams says supports the idea of multiple
susceptibility genes causing different types of cancers. These links will be
further investigated in the next phase of the study.
"The goal of our study is to identify the CRC genes in
susceptible patients to better understand who may be prone to develop CRC and
why," said Georgia L. Wiesner, M.D., lead author of the study.
"This study is step towards future the of genetic CRC
testing," Wiesner added.
The authors further explained that the genome-wide
scan used in this study would help physicians elucidate the genetic factors in
CRC in the future.
Once the genes are identified, physicians will be able
to use these genetic markers to identify "at risk" patients and to develop
better cancer screening strategies, such as colonoscopies well before standard
screening begins at age 50.
The study appears in
the March 7th issue of The American Journal of Human Genetics.