PTGS2 and neoplasm: In our study, the curative CEL (BBN+CEL-C) group, despite a lower COX-2 staining in non-neoplasic areas, which is in agreement with the treatment performed (Celecoxib was given between the end of BBN treatment, week 12, and the final time for bladder collection: week 20), severe COX-2 immunostaining in the tumor lesion was encountered, demonstrating a clear overexpression, similar to that encountered in the BBN-treated rats.