It’s a good news, bad news situation. Some women who have a breast biopsy are told that while they don’t have cancer, they do have atypical hyperplasia — cells that aren’t quite normal and might become cancerous someday. This happens to one-fourth of women undergoing breast biopsies but no one knows which individuals are at risk. Women whose atypia tissue expressed COX-2 enzymes were more likely to develop breast cancer subsequently, and that the more the enzyme expressed, the higher the risk.