Recently, research has been completed by scientists at the Lawrence Berkeley National Laboratory in Berkeley, Calif., to determine why. The researchers studying these irradiated breasts in young women have learned that the rate of stem-cell self-renewal is increased and that mammary stem cell are enriched sometime afterwards, and the scientists named these alterations as the primary causes of the young women’s increased risk.
What does this mean?
Estrogen receptors—proteins activated by the estrogen hormone—are critical during puberty to the normal development of the breast and of other female sexual characteristics. But it turns out that when mammary stem cells have been exposed during puberty to ionizing irradiation, they are damaged and can cause serious problems. That is, if such damaged stem cells are allowed to aid in breast development, then later in life the breasts will show a predisposition to developing estrogen-receptor-negative tumors—a bad type of breast cancer that is not only more difficult to treat but is typically also more aggressive than average.
The next steps in this breakthrough research
We have known for several decades that young girls who receive mantel radiation—radiation that is delivered to a large area of the neck, chest, and armpits to cover all the main lymph node areas in the upper half of the body—for treatment of childhood cancers grow up to have on average a 28 percent greater risk of developing breast cancer than does the general population.
The researchers now hope to find biomarkers that would identify those young girls who are at the greatest breast cancer risk due to radiation. (A biomarker is some measurable biological trait or feature that scientists can use as an indicator of the severity or presence of some disease state.)
These current studies will help us to now predict which young women fall into the 20-percent group as well as to determine how much radiation is actually needed to cause this problem. Many youngsters also get chest x-rays, for example, if they have chronic respiratory diseases or heart problems. It’s hoped that this research will not only further define the amounts of radiation that cause this predisposition to developing breast cancer but will also point to ways to block its negative impact on health later in life.