PPARG and neoplasm: The negative effect of PPARγ activation on tumor metastasis is further supported by findings that ciglitazone significantly reduces activity and total expression of MMP-2 by NCI-H157 and H1299 NSCLC cells [25] and that rosiglitazone enhances the activity of tissue inhibitor of metalloproteinases, which essentially decreases the net proteolytic activity of MMPs [45].