October 30, 2003
Genetic Mutations Linked to Cancer
More information about health can only help -- even if the information isn't so positive.
That seems to be the lesson of a new study confirming that Ashkenazi Jewish women with particular genetic mutations have a high risk of contracting breast cancer.
But the effects can be mitigated if girls with a family history of the mutation exercise when they enter puberty and live a healthy lifestyle as adults.
Some Ashkenazi Jewish women have mutations in the BRCA gene that makes the bearer susceptible to breast cancer. Other women also have these mutations, but their mutations have not been isolated because they have not been tested as often.
Mary-Claire King of the University of Washington was the main author of the study, which was published last week in the journal Science.
The study, which examined subjects at a dozen hospitals in New York, New Jersey and Connecticut, found that women with one of the BRCA gene mutations have an 82 percent chance of developing breast cancer by age 80. The average woman's risk at age 80 is 13 percent.
The risk factor was on the high end of previous estimates, but wasn't surprising, said Dale Mintz, director of women's health at Hadassah, the Women's Zionist Organization of America.
"It's what we all would have expected," she said.
Some 2 percent of Ashkenazi Jews carry the BRCA 1 or BRCA 2 mutations, according to the Human Genome Project in Washington.
The incidence of cancer among Ashkenazi Jews is not higher than among the general population, but more of their cancer risk stems from genetic factors.
While reports on genetic mutation have frightened many Ashkenazi Jewish women during the past few years, scientific inquiry is part of the solution, Mintz said. Jews "all want more information and are always looking to be educated better," she said.
In any event, said Jessica Mandell, a genetic counselor affiliated with Sarah Lawrence College in New York and a researcher-coordinator for the study, "carrying a mutation is not a guarantee you will develop cancer."
The study isolated 104 women who had one of the BRCA mutations and contracted cancer within a five-year period. Half of them had no strong family history of cancer.
That points to a need for increased genetic testing, since some doctors and other health professionals often identify cancer risk by scrutinizing family history -- and some women who had one of the BRCA mutations but no family history of breast cancer mistakenly had been told that they were not at a higher risk for cancer.
That's not true, Mandell said.
"A woman could have a high risk for cancer even if she doesn't have a strong family history," Mandell said.
Hadassah, which long has worked to push legislation through Congress that would prevent genetic discrimination in both health insurance and employment, doesn't take a stand on whether women should undergo genetic testing.
The genetic discrimination bill unanimously passed the Senate recently and currently is in the House of Representatives. President Bush has said he will sign the legislation if both legislatures pass it.
Women with the BRCA mutations are advised to have frequent mammograms. Some medical experts recommend that they take the drug tamoxifen to reduce their breast cancer risk. Some women avoid the disease entirely by having pre-emptive mammograms.
Meanwhile, experts continue to advise those who may be at risk to monitor their own health. The finding that carriers who exercise, particularly during the teenage years, are less likely to develop cancer early in life points to other actions that those at risk can take.
"This gives the family something proactive to help their female descendants," Mandell said.