Diffuse Large B-Cell Lymphomas: Heterogeneous Origin and Prognosisfrom the view of Contemporary Diagnostics

Overview

Background.
Diffuse large B-cell lymphomas represent a heterogeneous group of tumors with a different origin,morphological findings and a variable clinical prognosis. These tumors have been recently classified into twoprognostically relevant subgroups differing in the gene expression. The key genes suitable for routine diagnosticsof DLBCL have not been yet identified. The aim of this work was to study changes and expression of several genesand proteins participating in the genesis of DLBCL.Methods and Results. We analysed a group of 31 patients with diffuse large B-cell lymphomas. Basic clinical dataincluding follow-up of the patients were available. Tumors were examined by a panel of immunohistochemicalreactions with antibodies against CD20, CD79a, BCL-2, BCL-6, CD10, Ki-67 and TP53. FISH was used to detecta translocation t(14;18)(q32;q21) and/or a break in BCL6 region (3q27) suggestive of a translocation with a variabletranslocation partner t(3;?). PCR was utilized to detect the translocation t(14;18) and a clonal rearrangement of heavyand/or kappa chain of the immunoglobin genes.Conclusions. The expression of BCL-2 protein appeared to correlate with a higher mortality rate. The expressionof other proteins examined in the study did not correspond significantly with the clinical development of the disease.Tumors with follicular lymphoma as a component had significantly higher mortality rate than the tumors developingde novo. Moreover, higher mortality was evident in cases with higher values of the International Prognostic Index(IPI).

Key words:
diffuse large B-cell lymphoma, protein expression, clonality, translocations, prognosis, BCL-2.