On the other hand, in a human breast cancer cell line JIMT-1, prostasin expression was up-regulated by 1 mM ibuprofen at 24 h of treatment, but without a significant induction of COX-2 expression (data not shown), suggesting that the up-regulation of prostasin expression by IBU does not require a concomitant COX-2 up-regulation. This evidence concerns the gene PTGS2 and breast cancer.