In NSCLC cells, ZEB1 and Snail were found to be repressors responsible for the regulation of E-cadherin downstream of Cox-2/PGE2[37], whereas in bladder cancer cells Cox-2 inhibitors downregulated all of the E-cadherin repressors examined: Snail, Slug, Twist, and ZEB1 [43]. This evidence concerns the gene PTGS2 and non-small cell lung carcinoma.