Increased Expression of Cyclooxygenase-2 is Associated with the Progression to Cirrhosis

Background/Aims: To investigate the degree of cyclooxygenase-2 (COX-2) protein expression in chronic hepatitis and cirrhosis. Methods: COX-2 protein expression was evaluated in 43 cases of chronic hepatitis and 24 cases of cirrhosis using immunohistochemical techniques. The COX-2 immunohistochemical staining score was assessed using the scoring systems of Pazirandeh et al and Qiu et al. and each scoring system was based on a sum of the parameters of staining intensity and distribution. Results: The mean COX-2 expression scores in chronic hepatitis and cirrhosis were $2.5{\pm}1.3$ vs. $3.3{\pm}1.1$ (p = 0.008), and $3.2{\pm}2.0$ vs. $4.5{\pm}1.7$ (p = 0.006), respectively, based on the Pazirandeh et al. and Qiu et al. scoring systems. The percentage samples of high COX-2 expression score (4 to 5) in chronic hepatitis and cirrhosis were 16.3% vs. 45.8% (p = 0.022), and 23.3% vs. 50% (p = 0.021), respectively, based on the two scoring systems. The mean COX-2 expression scores based on the severity of hepatic fibrosis scored using Ishak's modified staging system (fibrosis score 0 to 3 vs. 4 to 6) were $2.4{\pm}1.3$ vs. $3.2{\pm}1.1$ (p = 0.009), and $3.1{\pm}2.0$ vs. $4.3{\pm}1.8$ (p = 0.009), respectively, based on the two scoring systems. Conclusions: COX-2 expression was significantly higher in liver cirrhosis group than in chronic hepatitis. COX-2 expression scores according to Ishak's staging was significantly higher in the advanced fibrosis group. COX-2 may play a role in the progression of hepatic fibrosis.