Diffuse Large B-cell Lymphoma에서 Bcl-6와 CD 10 단백 발현의 의의

Abstract

Background: Diffuse large B cell lymphoma is the most common lymphoma subtype, characterized by marked clinical and biologic heterogeneity. Recently, diffuse large B cell lymphoma has been subclassified as germinal center B-cell-like(GCB) and in vitro activated peripheral blood B-cell types(APB) using tissue microarrays. Diffuse large B cell lymphoma patients with an APB-type of gene expression profile do significantly worse than matched GCB-type patients. Methods: To determine if the expressions of Bcl-6 and CD 10 could be prognostic markers in diffuse large B cell lymphoma, I performed immunohistochemical study of Bcl-6 and CD 10 expressions on paraffin-embedded tumor tissue sections from 30 diffuse large B cell lymphoma patients. I then correlated the expression of CD 10 and Bcl-6 protein with various clinical parameters, especially IPI(International prognostic index). Results: Thirty cases of diffuse large B cell lymphoma were classified into low/low-intermediate and high-intermediate/high risk groups according to IPI. The median age of patients was 56 years (range, 24~81) and male to female ratio 20:10. There were 17 cases(56.7%) in the low/low-intermediate risk group and 13 cases(43.3%) in the high-intermediate/high risk group. The expressions of Bcl-6, Bcl-2, and CD 10 were demonstrated in 12 cases(70%), 15 cases(50%) and 2 cases (6.7%) of 30 patients, respectively. Low/low-intermediate risk group tends to have higher Bcl-6 (+) expression than high-intermediate/high risk group without statistical significance. Patients with Bcl-6 (+) expression had favorable overall survival compared with patients with Bcl-6 (-) expression(p=0.0135). In the low/low-intermediate risk group, Bcl-6 (+) expression showed significantly better prognosis than the Bcl-6 (-) expression(p=0.0056). Multivariate analysis showed that the results for overall survival were independent of IPI and Bcl-6 expression. Conclusions: The Bcl-6 (+) expression and low/low-intermediate risk IPI is an independent predictive and prognostic factor associated with better clinical outcome in patients with diffuse large B cell lymphoma. The prediction of outcome in diffuse large B cell lymphoma using clinical prognostic variables(e.g. IPI) performs well in many cases. However, molecular prognostic factors such as Bcl-6 may supplement IPI in predicting the prognosis of diffuse large B cell lymphoma patients.