New NCI Initiative to Identify Genetic Risks for Breast and Prostate Cancer
NCI has launched an initiative to identify genetic alterations that make people susceptible to prostate and breast cancer, two of the most commonly diagnosed cancers in the United States.
The Cancer Genetic Markers of Susceptibility (CGEMS) program is a 3-year initiative, funded for $14 million, that will conduct scans of the entire human genome (genotyping) to identify common, inherited gene mutations that increase the risks for breast and prostate cancer. The initiative will begin with the scanning of a total of 2,500 samples from men who have been diagnosed with prostate cancer, and men who have not. San Diego-based Illumina, Inc., will conduct the rapid genotyping for the project.
"The CGEMS initiative represents the largest, comprehensive undertaking to identify the genetic risk factors for two cancers that take the lives of a combined total of more than 70,000 men and women every year," said NCI Deputy Director for Strategic Scientific Initiatives Dr. Anna Barker. "This project promises to provide a needed database to support the development of novel strategies for the early detection and prevention of these diseases."
The most common human genetic variations are called single nucleotide polymorphisms, or SNPs. Previous studies have successfully identified single gene mutations that cause cancer or are linked to other inherited diseases. These studies have provided early insights into potential mechanisms of inherited cancer susceptibility, but these mutations are rare in the general population and directly related to only a small proportion of human cancer. In fact, most human cancer risk appears to be due, at least in part, to mutations that have low penetrance, meaning that they convey a low risk for cancer, but combinations of these mutations increase risk.
One of the main goals of CGEMS is to identify genetic alterations that contribute to cancer risk, particularly the common low-penetrance, low-risk mutations. These alterations are also often referred to as susceptibility or modifier genes, since it is thought that they affect risk by increasing or decreasing a person's susceptibility to the cancer-causing effects of environmental and lifestyle exposures.
What makes CGEMS and other association studies different from candidate gene studies is that these association studies investigate the entire genome, with no assumptions about which alterations cause prostate or breast cancer. In addition, CGEMS has incorporated important follow-up studies in its design. The promising SNPs uncovered in the scan will be analyzed and validated in a series of large population-based studies. Once validated, the SNPs will be further investigated to develop new strategies for prevention, earlier detection, and treatment of these cancers.
CGEMS will be coordinated through NCI's Division of Cancer Epidemiology and Genetics (DCEG), Core Genotyping Facility, and Office of Cancer Genomics. The project will draw upon the expertise of scientists both within and outside NCI, and will use the latest genetic technologies to scan the human genome by analyzing as many as 500,000 or more SNPs in each cancer case or control individual.