The Abundance of CD20 Immunoexpression Correlates with the Outcome of Diffuse Large B-Cell Lymphoma

초록

Background: CD20 is a B-cell specific antigen expressed in the cell membrane of mature B-cells. Anti-CD20 agents, such as rituximab are used for immunotherapy for B-cell lymphomas. The aim of this study was to correlate the abundance of CD20 expression in diffuse large Bcell lymphoma (DLBCL) with clinical outcome of the patients. Methods: We used ImmunoMembrane, a free web-based image analysis tool, to perform semiquantitative assessment of CD20 expression in a well-defined cohort of 48 DLBCL patients treated with CHOP or RCHOP therapy. Tissue microarray (TMA) was used to represent with duplicate cores (1 mm) of the initial diagnostic samples. The TMA sections were immunostained for CD20, BCL2, BCL6, CD10, MUM1, and Ki-67. Receiver operating characteristic curve analysis was used to determine prognostic cut-off value of the low CD20 immunoexpression. Results: Nineteen (39.6%) patients with low CD20 immunoexpression showed significantly inferior overall survival in univariate (log-rank p=0.042). The tendency also remained when the patient were stratified by status of R-CHOP (log-rank p=0.062). In multivariate analysis, only the low CD20 expression (hazard ratio [HR], 5.40; 95% confidence interval [CI], 1.19 to 24.53; p=0.029) and extranodal involvement (HR, 13.83; 95% CI, 2.46 to 77.61; p=0.003) were associated with poor overall survival. Conclusions: Semiquantitative estimation of CD20 immunoexpression level in DLBCL can be used to identify a subgroup of DLBCL patients with poor outcome. Key Words: Lymphoma, large B-cell, diffuse; CD20; Prognosis; Immunohistochemistry