PTGS2 and breast cancer: Previous Research has revealed two distinct mechanisms for COX-2 mRNA regulation: first, in breast cancer cells, alternative splicing that retains intron 7 between exons 7 and 8 targets the transcript for NMD; second, the long 3’-UTR harbors multiple AU-rich elements (AREs) within exon 10 that destabilize the COX-2 mRNA (17).