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Whole Genome Sequencing Not Informative For All
With sharp declines in the cost of whole genome sequencing, the day of accurately deciphering disease risk based on an individual’s genome may seem at hand. But a study involving data of thousands of identical twins by Johns Hopkins investigators finds that genomic fortune-telling fails to provide informative guidance to most people about their risk for most common diseases, and warns against complacency born of negative genome test results.
Identifying New Genes
A number of colon cancer susceptibility genes have been discovered at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, including the APC gene, which predisposes to Familial Adenomatous Polyposis, the MSH2, MLH1, PMS1, and PMS2 genes, all of which are associated with Hereditary Nonpolyposis Colorectal Cancer, and the APC I1307K mutation, which is found most commonly in the Ashkenazi Jewish Population and increases the risk of colon cancer.
Studies are underway to identify additional genetic factors associated with colon cancer development using families enrolled in the Johns Hopkins Hereditary Colorectal Cancer Registry.
In addition, the Sidney Kimmel Comprehensive Cancer Center investigators also recently discovered linkage of a possible familial prostate cancer gene to chromosome 1.
Additional work is being done to isolate and characterize this and other potential genes. Families with familial pancreatic cancer are being studied to help researchers and clinicians understand the genetic basis of this disease. Previously, Hopkins investigators characterized germline mutations of the p16, BRCA2 and PALB2 genes in pancreatic cancer. Genetic linkage studies for potential cancer susceptibility genes that predispose to lung cancer development are also active.
A Genetic Revolution
The complexity of their genetic discoveries has been likened to finding one two-letter transposition within 20 volumes of “Encyclopedia Brittanica” and then figuring out how it got there. Some scientists consider them to be of the magnitude of finding a cause for polio. But as transforming as these discoveries have been in the cancer world, they started simply and quietly in 1983 in a converted supermarket on the Johns Hopkins East Baltimore Medical Campus.
Improving Counseling Methods
Sidney Kimmel Comprehensive Cancer Center researchers conducted a nationwide survey of physicians and genetic counselors concerning the adequacy of counseling given to patients tested for a gene linked with colon cancer. Investigators are currently developing, implementing, and evaluating a model informed consent process that integrates the perceptions of consumers and providers in relation to BRCA1 testing.
A study was also completed that contributed empirical data concerning the values, beliefs, and experiences of persons with genetic conditions (including hereditary colon cancer) regarding informational privacy and access to health insurance. Researchers are also currently investigating the efficacy of in person versus telephone genetic counseling and disclosure methods.
Improving Testing Methods
Sidney Kimmel Comprehensive Cancer Center researchers developed a testing methodology (protein truncation testing) that identifies genetic mutations in the APC gene and provides an opportunity to use genetic testing in families with Familial Adenomatous Polyposis (a form of inherited colon cancer).
Investigators are also looking at factors that influence physicians' adoption of new genetic tests and their attitudes toward how tests should be provided.
Discovering Clinical Treatments for Genetic Disorders
Sidney Kimmel Comprehensive Cancer Center C researchers identified hundreds of genes that were overexpressed in pancreas cancer using a novel technique called SAGE. These overexpressed genes may be used to develop new blood markers that are increased in pancreatic cancer patients and may lead to a test that will aid in the earlier detection of pancreatic cancer. Similar analysis was also performed in colon cancer. Tracking long term results of prophylactic surgeries, medical surveillance choices, and preventative interventions:A studying tracking women who have undergone prophylactic mastectomy is currently underway. Additional research into the preventative interventions and surveillance choices of patients is being planned through the Mid-Atlantic Cancer Genetics Network. The Mid-Atlantic Cancer Genetics Network evaluated methods of ovarian surveillance, as well as the efficacy of breast MRI. Investigators also evaluated the use of ductal lavage for breast cancer screening.