COX-2 expression is marker for cancer development in some benign breast biopsies

ROCHESTER, Minn. -- 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.

In their quest to discover who is at risk, researchers at Mayo Clinic (http://mayoresearch.mayo.edu/mayo/research/womens_cancer/breast_excellence.cfm) are building a biopsy profile to try to predict cancer outcome, and in the March 11 online edition of the Journal of the National Cancer Institute (http://jnci.oxfordjournals.org/rss/recent.xml), they report finding a new variable to add to this profile.

The research team discovered that 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.

Specifically, 20 years after a biopsy in which atypia was found, 31 percent of women with high levels of COX-2 in their atypia sample had developed breast cancer, versus 14 percent of those with no COX-2 expression. For those with moderate levels of COX-2, 24 percent had developed breast cancer.

“Based on these findings, COX-2 expression in atypia may be a biomarker of risk of progression to breast cancer,” says the study’s senior investigator, Mayo Clinic oncologist Lynn Hartmann, M.D (http://mayoresearch.mayo.edu/mayo/research/staff/hartmann_lc.cfm). “COX-2 is a relevant candidate because it drives a number of malignant features and has been shown to be important in breast cancer.