ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Wednesday, November 13, 1996 TAG: 9611130048
SECTION: NATL/ITNL PAGE: A-3 EDITION: METRO
DATELINE: CHICAGO
SOURCE: Associated Press
A flawed enzyme present in millions of Americans may raise the risk of breast cancer in women who smoke, a study suggests.
Heavy smokers who had reached menopause had about four times the risk of breast cancer as nonsmokers who also had the flawed enzyme, researchers reported in today's Journal of the American Medical Association.
Postmenopausal women who had the flaw and had smoked any amount at or before age16 ran a similar risk. That supports the theory that exposure to toxic agents may be most harmful during breast development.
The researchers looked at a genetic flaw that causes people to produce a slow-acting form of the NAT2 enzyme, a substance that helps deactivate cancer-causing agents in the body.
The flawed enzyme is believed to be present in more than half of all white men and women in the United States. It is even more prevalent in people of Middle Eastern descent but less common among other ethnic groups.
``If these findings are replicated, I think the implications are quite important, because there's an alarming trend now. Young girls are smoking now at a higher rate than young boys are,'' said epidemiologist Christine Ambrosone, who led the research. ``It's one more reason for women not to smoke and especially for young girls not to begin smoking.''
Ambrosone conducted the National Cancer Institute-funded research while at the State University of New York at Buffalo.
Previous research has shown that people with slow NAT2 may be more likely to get bladder cancer, but none found an added risk from smoking, the researchers said.
The new study ``suggests that defective enzymes, fired by cigarettes, increase the risk for breast cancer,'' Dr. Henry Lin of the pediatric Division of Medical Genetics at Harbor-UCLA Medical Center in Torrance, Calif., said in an accompanying editorial.
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