Washington, March 8 : 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 susceptibility gene.
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.