Aug 28, 2003 - 2:20 pm
CHICAGO A gene present in nearly one in eight people is the most commonly inherited cancer susceptibility gene identified so far, increasing cancer risk in carriers by 26 percent, according to a study published by researchers at Chicago's Northwestern Memorial Hospital in today's Journal of Clinical Oncology. More common than the BRCA gene mutations, Transforming Growth Factor Beta Receptor 1*6A (TGFBR1*6A) may increase risk of breast cancer by 48 percent, ovarian cancer by 53 percent, and colon cancer by 38 percent.
"This is an exciting finding because TGFBR1*6A is a common gene that may cause a large number of cancers. In the near future, it will be commonplace for people to know what genes make them more susceptible to cancer, and we'll have many more options for preventing those cancers," says Boris Pasche, M.D., Ph.D., F.A.C.P., director of Northwestern's Cancer Genetics Program, assistant professor of medicine at the Feinberg School of Medicine and a researcher at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
Researchers analyzed seven published studies and pooled those results to conclude that the TGFRB1*6A gene may be to blame for approximately 7 percent of all breast cancers, nearly 11 percent of all ovarian cancers and 5.5 percent of all colon cancers, across a variety of ethnic groups. "These findings should put TGFBR1*6A on the map with better known cancer susceptibility genes such as BRCA1 and BRCA2 that have been implicated in an estimated 5 to 10 percent of all breast and ovarian cancers," said Dr. Pasche.
Altered genes trigger all cancer. "Most cases of breast, ovarian and colon cancers are caused by damage to the genes that builds up over a lifetime, but some people are born with a high risk of the disease," explains Pasche. "When inherited, the TGFRB1*6A gene makes people susceptible to having certain cells grow and divide uncontrollably, which may contribute to cancer development."
Northwestern's Cancer Genetics Program, which was launched last fall, is a comprehensive cancer genetics program that provides cancer predictive gene testing and genetic counseling. TGFBR1*6A testing is currently only offered at Northwestern as part of a research protocol at the Cancer Genetics Program, but Dr. Pasche predicts that testing for this gene will enter the mainstream of genetic testing in the near future. "The results of this study will certainly spark interest in genetic testing and counseling for TGFBR1*6A," he says.
"By spotting a mutated gene in an individual, we can sometimes detect cancer years earlier through increased cancer screening. Through genetic counseling and genetic testing, we aim to reduce the incidence of cancer among individuals with increased risk," explains Taya Young, MS, a genetic counselor at the Northwestern Cancer Genetics Program. Currently, there are several options for people who find themselves at increased risk of breast, ovarian and colon cancers. These include preventive drug therapy, increased surveillance, lifestyle changes and preventive surgery. "Genetics is still a very new specialty, and we are just at the tip of the iceberg in discovering how we can maximize its full potential," says Dr. Pasche.
Virginia Kaklamani M.D., an oncologist at Northwestern Memorial Hospital and assistant professor of medicine at the Feinberg School of Medicine, is the first author of the study. She adds, "The testing of TGFBR1*6A is not ready for primetime yet. We still have to understand its role in relation with other genes that we commonly test for, such as BRCA1 and BRCA2.
However, in the foreseeable future, we may be able to identify high-risk women more precisely because of the TGFBR1*6A mutation and prevent many cases of breast and ovarian cancer."
About Northwestern Memorial's Cancer Program
With the important affiliation of Northwestern Memorial Hospital (NMH), Northwestern Memorial Faculty Foundation (NMFF) and The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, NMH has established a national reputation as a leader in providing state-of-the-art, patient-focused and family-centered care. The NMH cancer program is ranked among the top 40 in the country for this specialty by U.S. News and World Report's Best Hospitals issue.
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