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Cancer Genetics Unit offers well-planned cancer management

From the “letters” of the genetic code, to the breast cancer susceptibility gene BRCA1, to HNPCC, a hereditary form of colon cancer pinpointed to gene defects – genetic codes sound more like alphabet soup than the cutting-edge of medical research.

Yet, hiding behind letters lie real information about the human body.

In the past few years, scientists have discovered genes that lead to dramatically increased cancer risk when they become damaged. Blood tests that detect these damaged genes can identify high-risk patients before the appearance of the first signs of cancer.

And that has prompted a new need – clinicians and counselors who can help individuals make sense of their own genetic code.

Since October, the Cancer Genetics Unit at USC/Norris Comprehensive Cancer Center and Hospital has offered a setting in which patients can receive education and counseling about their cancer risk, explore their options for cancer predisposition gene screening, and plan preventive care based on their genetic status.

Robin Clark, pediatrician and a medical geneticist, heads up the unit.

“Hundreds, even thousands of healthy people in Southern California alone may be able to prevent cancer in themselves and their loved ones by learning more about their genetic code,” Clark said.

Women with inherited alterations in the BRCA1 breast cancer predisposition gene have up to an 85 percent chance of being diagnosed with breast cancer by age 70. They also face a greater risk of developing ovarian cancer.

For individuals with gene alterations that predispose them to colon cancer, the risk reaches 75 percent by age 65. These individuals also face a higher risk of developing stomach, ovarian and endometrial cancers.

The new unit blends the “philosophies” of geneticists and oncologists, says colon cancer researcher Heinz-Josef Lenz, who coordinates the unit’s research. “Oncologists are usually focused on the diagnosis and treatment of a single patient. Working with geneticists opens up a family approach,” Lenz said.

The inherited cancers that have been identified so far make up only 5 to 10 percent of all cancers; the rest are considered sporadic. That means a negative test for one of the genes doesn’t necessarily mean you are risk-free.

On the other hand, not every single person with alterations in one of the genes will develop cancer.

These considerations, combined with concerns over possible genetic discrimination, the psychological stress of knowing whether you carry a high-risk genetic alteration and, for some cancers, limited options for interventions, make the decision to get tested a complex one.

In general, only about half of patients referred for genetic risk assessment decide to proceed with genetic testing.

“People really need to think this through before they decide,” Clark said, noting that this is exactly the point of having educational and counseling services available at the unit.

However, “as we develop more and better preventive interventions, genetic testing will become more and more utilized,” Clark predicts.

For colon cancer, knowing whether you carry a high-risk gene can be life-saving.

Currently, however, there is not much data on how best to prevent breast cancer in carriers of the altered genes.

“There is still this ‘black hole’ of knowledge about what having these altered genes means,” Lenz said.

He hopes to find better ways to detect, prevent and treat hereditary cancers.

Right now Lenz is leading an investigation looking at whether breast cancer patients with a mutation in the BRCA1 gene should be treated with different chemotherapies than patients with sporadic breast cancer. Another remaining question is how the specific location and nature of gene alterations influence the presentation and course of the cancer.

Monica Alvarado, assistant professor of clinical pediatrics, is the team’s genetic counselor. Phyllis Rideout, assistant director of the USC/Norris Cancer Center, oversees the educational and research components of the program.

“Genetics counselors are experienced in helping individuals understand the effects that genetic information can have on them and their families,” Alvarado said.

For more information about the Cancer Genetics Unit call 1-59-NORRIS

Cancer Genetics Unit offers well-planned cancer management

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