OBJECTIVETo investigate the protein expression of cyclooxygenase 2 (COX-2) and nuclear factor kappa B (NF-kappaB) in gastric mucosa-associated lymphoid tissue (MALT) lymphoma and its clinical significance.

METHODSProtein expression of COX-2 and NF-kappaB in gastric MALT lymphoma were examined by immunohistochemistry of Envision two-step method. The correlations of COX-2 and NF-kappaB expression with Helicobacter pylori (Hp) infection, clinical stage, depth of tumor invasion, tumor size, recurrent rate and treatment were analyzed by univariate, multivariate and Pearson analysis.

RESULTSThe positive expression of COX-2 and NF-kappaB in gastric MALT lymphoma were 48.9%(23/47) and 36.2% (17/47) respectively, and a positive correlation was found between these two factors(r=0.326,P<0.05). Moreover, COX-2 expression was positively correlated with Hp infection,clinical stage, depth of invasion and tumor size (P<0.05). Univariate analysis showed that the overall survival of gastric MALT lymphoma patients with positive COX-2 protein (59.9 months) was shorter than that of patients with negative COX-2 protein (77.8 months), but the difference was not significant (P>0.05). The survival was significantly shorter in gastric MALT lymphoma patients with positive NF-kappaB protein (26 months) than that of patients with negative NF-kappaB protein (123.2 months)(P<0.05). Multivariate Cox regression analysis revealed that clinicopathological stage was independent prognostic factor, and associated with short survival.

CONCLUSIONUp-regulated expression of COX-2 and activation of NF-kappaB are associated with Hp infection in gastric MALT lymphoma, and their protein expression is correlated with the development of tumor and prognosis.