Prognostic significance of cyclooxygenase-2 expression in pediatric Hodgkin and non-Hodgkin lymphomas with or without Epstein-Barr virus latent infection

The aim of this study is to investigate the expression of cyclooxygenase-2 (COX-2) and the relationship between COX-2, prognosis and Epstein-Barr virus (EBV) in pediatric Hodgkin (pHL) and non-Hodgkin lymphomas (pNHL). Cyclooxygenase-2 is frequently overexpressed in various tumors. COX-2 inhibitors' potential use as a therapeutic target in onco-hematology and its relation with EBV is a contemporary question. A potential role for COX-2 in EBV-associated human cancers was suggested. The role of COX-2 in EBV-related oncogenesis of pHL and pNHL is not studied. The expression of COX-2, latent membrane protein 1 and Epstein-Barr virus-encoded early RNA was detected by immunohistochemistry and in situ hybridization in 63 pHL and 70 pNHL. The results were scored as positive or negative. The statistical significance was assessed by correlation, survival analysis, and nonparametric tests. In pNHL cases, the mean age was 7.16∈±∈3.72. EBV was positive in 18 cases, COX-2 in 16 cases (22.8%). Expression of COX-2 did not correlate with age, sex, stage, phenotype, histology, EBV positivity, and response rate to therapy. In pHL cases, the mean age was 8.46∈±∈3.54. EBV was positive in 52(82.5%), COX-2 in 36(57.1%) cases. The expression of COX-2 protein did not correlate with age, sex, stage of disease, EBV positivity, and response to therapy. COX-2 expression was higher in nodular sclerosing and lymphocyte-rich histology. In log rank analysis, no statistical significance for prognosis was observed. In this series, COX-2 was found to be expressed in the minority of pNHL tissues and more than half in pHL cases especially in NS type. This might be related with fibrosis of NS cases. It did not correlate with prognosis. COX-2 expression did not seem to have a synergistic role with EBV in the pathogenesis of pediatric lymphomas. It will be useful studying the relationship of COX-2 expression with apoptotic and other factors in pediatric lymphomas. © 2007 Springer-Verlag London Limited