Celecoxib may regulate a cell's use of estrogen - might help explain the drug's anticancer properties

Six months of treatment with celecoxib (Celebrex) in women at risk of developing breast cancer results in the reduction of estrogen receptor expression in breast cells, a research team at The University of Texas M. D. Anderson Cancer Center has found.

The surprising insight - that celecoxib may regulate a cell's use of estrogen - could help explain the drug's observed anticancer properties, says the study's lead author, Banu Arun, M.D., associate professor in the Department of Breast Medical Oncology.

"Since estrogen receptor expression is a marker of proliferation, this finding confirms celecoxib's antiproliferative properties," she says. "This is a preliminary, but exciting, finding that has not been reported in clinical chemoprevention studies before."

To date, the study has enrolled 40 women at high risk of developing breast cancer. Each woman agreed to undergo a fine needle aspiration and ductal lavage to remove breast epithelium cells both before and after six months of celecoxib treatment. These samples were available for analysis in 26 high-risk women. The researchers assessed the difference in estrogen receptor levels before and after treatment.

They found that the average pre- and post-treatment estrogen receptor expression was 30.8 percent and 21.8 percent, respectively, which is a statistically significant difference. Arun says they are continuing to examine the impact of celecoxib on other cancer risk markers in breast cells, such as EGFR, HER2, Ki-67 and Bcl-2.