A single bad gene appears to cause a significant share of breast cancer in young women, especially Jews, in whom it may trigger more than a quarter of all cases under age 40.
A whirlwind of research over the past two years has pinpointed a gene that is often to blame when breast cancer clearly runs in families.
Now, two new studies show for the first time that this same gene is frequently the cause whenever the disease strikes women in their 20s and 30s, even if there is no strong pattern of breast cancer among the victim’s close relatives.
“This is an important finding,” said Dr. Richard Klausner, director of the National Cancer Institute. “It takes genetic susceptibility the next step - from individuals who are members of preselected families with a history of cancer - and now looks at all young women.”
The younger women are when they get breast cancer, the more likely that it is caused by a miscue in the recently discovered gene, called BRCA1.