A new study from researchers at The University of Texas MD Anderson Cancer Center finds that, in healthy women, some breast cells that otherwise appear normal may contain chromosome abnormalities typically associated with invasive breast cancer. The findings question conventional thinking on the genetic origins of breast cancer, which could influence early cancer detection methods. The study, published today in Nature, discovered that at least 3% of normal cells from breast tissue in 49 healthy women contain a gain or loss of chromosomes, a condition known as aneuploidy, and that they expand and accumulate with age. This poses questions for our understanding of “normal” tissues, according to principal investigator Nicholas Navin, Ph.D., chair of Systems Biology.