Expression of cyclooxygenase-2 and embryonic lethal abnormal vision-like protein HuR in gallbladder carcinoma

Background: Cyclooxygenase-2 (COX-2) is an enzyme that promotes proliferation of tumor cells. HuR is a member of the family of embryonic lethal abnormal vision-like proteins. Recent studies show that cytoplasmic HuR stabilizes the mRNA of COX-2 and regulates the expression of COX-2. Moreover, cytoplasmic HuR expression is associated with a poorer prognosis for patients with some cancers. The aim of this study was to investigate the expression patterns of and the relationship between COX-2 and HuR in gallbladder carcinoma. Methods: We analyzed COX-2 and HuR expression by immunohistochemical staining of 108 gallbladder carcinomas. Results: COX-2 expression and nuclear and cytoplasmic HuR expression were seen in, respectively, 61 (56.5%), 77 (71.3%), and 4 (3.7%) cases. COX-2 and nuclear HuR were simultaneously expressed in 44 of the 108 samples without any quantitative association between the levels of each. COX-2 expression correlated with tumor stage, differentiation (based on histology), lymph node metastasis, perineural invasion, and survival. Nuclear and cytological expression of HuR did not correlate with any clinical parameters. Conclusions: COX-2 expression but not HuR may play an important role in the prognosis of patients with gallbladder carcinoma.