In N-butyl-4-N-(4-hydroxybutyl) nitrosamine (BBN)-induced rat urinary bladder cancer model, COX-2 is also upregulated in both pre-neoplastic and neoplastic lesions [40] and elevated expression of COX-2 is correlated with higher levels of PGE2 in many cancers [41]. Here, PTGS2 is linked to urinary bladder cancer.