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Expert: New Cancer Link Result is a Medical Step, Not Reason to Panic

Don’t panic. That’s the message from an expert on Jewish health-related issues after a study reported that Ashkenazi Jews are two to three times more likely to develop colon cancer if they have a mutation of a single gene.

The study of DNA from more than 3,000 Ashkenazi Jews in New York and northern Israel appeared last Friday in the journal Science. Earlier studies had shown that mutation of both copies of the BLM gene causes a disorder called Bloom syndrome, but this study shows that it takes only a single flawed BLM gene to increase the risk of colon cancer.

Only about 1 percent of Jews of Eastern European descent have the single BLM gene mutation.

“Every step science takes is significant,” says Dale Mintz, director of women’s health at Hadassah, the Women’s Zionist Organization of America. “The more information they’re gathering, the more people they can diagnose.”

Indeed, the senior author of the study said it may be a first step toward a basic understanding of what causes colon cancer in general.

“Although this finding relates only to Ashkenazi Jews, we think the mechanism will be the same for all colon cancers,” said Kenneth Offit, the senior author of the study and a researcher at Memorial Sloan-Kettering Cancer Center in New York.

Colorectal cancer is the leading cause of cancer death in Israel and the second leading cause of cancer death in the United States, though it is considered a preventable disease.

There are many steps people can take to reduce their susceptibility to colon cancer. A generally healthy lifestyle, including regular exercise, is recommended.

Smoking has been linked to colon cancer. A diet low in fats and high in fiber has been linked to lower risk of colon cancer, but this view is not universally accepted.

Patients concerned about colon cancer should discuss the issue with their doctor. Most guidelines call for colonoscopies beginning around the age of 50, and earlier if there is a family history of colon cancer.

Genetic tests are not yet available for the BLM gene mutation, says Mintz of Hadassah, which is conducting colon cancer research at its Ein Kerem hospital in Jerusalem.

It’s possible that such tests may one day become available with further research.

Some health professionals worry that such testing could lead to health insurance discrimination against those found to have the gene.

The finding is just the latest one identifying a certain genetic mutation among Ashkenazi Jews. The most well- known of such mutations, the BRCA1 and BRCA2 mutations, are linked to a heightened risk of breast cancer.

It is unclear why so many mutations are being found among Ashkenazi Jews. One view attributes the prevalence to generations of inmarriage in Eastern Europe.

The willingness of Jews of Eastern and Central European descent to participate in studies may also be a contributing factor.

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