Scientists have discovered a breast cancer gene, a finding that may allow the early detection of the deadly disease and could lead to new treatments.

Biologist Patricia Berg at George Washington University says her team has found a gene, called BP1, that was activated in 80 percent of the breast tumors they studied.

"We actually were surprised at the fact that 80 percent of women's breast tumors were BP1 positive," she said. "Which is an extremely high number. And we do think this is an early significant finding."

Speaking at a news conference at George Washington University, Ms. Berg cautions that her findings are just the first step. Other scientists will need to confirm them.

But her boss, department head Allan Goldstein of the George Washington University Medical Center says, if her findings hold up, "Her team has in effect discovered what may turn out to be the face of the enemy."

Breast cancer is the most common form of cancer among women worldwide, claiming the lives of nearly 375,000 women each year.

Ms. Berg says she hopes her findings will help to develop a blood test that will allow doctors to detect breast cancer early. Doctors say early detection is the key to surviving cancer.

Ms. Berg says researchers can also begin to study drugs already in the works that act on BP1 that look promising in the laboratory.

Ms. Berg's team had earlier found the gene turned on in patients with blood cancer, or leukemia. They found the gene was involved in regulating how cells grow. Since cancer is essentially unchecked cell growth, Ms. Berg said, "We reasoned that maybe it may be involved in other kinds of cancer as well as leukemia. We decided to look at breast cancer first. And lo and behold, there it was."

The hardest-to-treat breast cancer tumors turned out to be the most likely to have the BP1 gene switched on.

Two in five breast cancer patients have these kinds of tumors. They are called estrogen-receptor-negative, or ER-negative, tumors.

All of the ER-negative tumors Ms. Berg's team studied had the BP1 gene turned on. The gene was also switched on in three quarters of the other kind of breast cancer tumors, ER-positive tumors.

African-American breast cancer patients were more likely than caucasians to have the BP1 gene switched on. Studies show African-American women are less likely to survive breast cancer than caucasian women. According to Ms. Berg, one part of the reason is socioeconomic.

"But it has been speculated that it might be due to a genetic factor, and so this is a possible candidate," she said.

Ms. Berg added that, as a scientist, and a mother of a daughter, she hopes the findings can make a real difference in dealing with breast cancer.