MMP9 and neoplasm: In particular, MMP-2 and MMP-9 activity appears to be inhibited by celecoxib in our study, the first by up-regulation of MMP antagonists (TIMP1, TIMP2, and TIMP3), the latter by up-regulation of the MMP-9 inhibitor RECK. An involvement of selective COX-2 inhibition in matrix stability by decreasing MMP activity and tumour invasiveness has been previously demonstrated in breast and CRC cancer models [44,45], thus being in good agreement with our data.