Henda Salmeron has a keen interest in breast cancer--that's because a year ago this month she was given the worst news of her life.

"I was diagnosed with a four centimeter tumor that went undetected through mammography," Salmeron said. "They anticipate that it was there for three years."

Because the tumor went undetected for so long Salmeron had two lumpectomies and radiation treatment--but now a simple blood test might detect breast cancer far better than a mammogram.

The test looks for high levels of a protein called epidermal growth factor receptor. Researchers studied a large group of women and found that those with high levels of the protein were three times more likely to be diagnosed with cancer later on. The protein was unusually high up to 17- month before they were diagnosed.

Baylor-Grapevine oncologist Thomas Anderson calls the research exciting.

"Mammography doesn't really work well for women who have dense breasts, it can't identify some of these small tumors so if there was a blood test that could do the same thing or even better then that would be a great advance," Dr. Anderson said.

Salmeron said that's what caused her tumor to stay hidden for three years.

"I have dense breast tissue and it's because of dense breast tissue that my four centimeter tumor went undetected by mammography because the largest part of that tumor was in the densest part of my breast," Salmeron said.

About 20% of of all tumors are never spotted in women with dense breast tissue. The scientific breakthrough comes too late for Salmeron who is now cancer free but for other women--someday soon tumors may have nowhere to hide.

"It can save a lot of lives because today when you have breast cancer in most cases it's very treatable if it's early detected," Salmeron said.

Researchers said it's too early to tell if the test can be used alone to diagnose cancer but that it may be used along with other screening processes like self examinations and mammograms.