Treatment with celecoxib regulates gene expression in MDA-MB-231 cells. Differential gene expression was assessed by comparing MDA-MB-231 cells treated with or without 40 mmol/l celecoxib for 24 hours using the Affymetrix Human Genome 133A Gene Chip. Replicate microarray analyses were employed. A total of 44,760 genes were initially evaluated, and of these 1069 had a twofold or greater change. Selected results compare genes of interest associated with important cell pathways. Bars on the right represent an increase in gene expression and bars on the left indicate a decrease. COX, cyclo-oxygenase.