Molecular prognostic factors in diffuse large B-cell lymphoma.

The treatment of patients with diffuse large B-cell lymphoma (DLBCL) has been guided traditionally by clinical parameters such as the Ann Arbor Staging Classification for Hodgkin's disease. Although the International Prognostic Index (IPI) represents the most widely accepted prognostic model, there is still a marked variability in outcome within identical IPI subgroups, reflecting the heterogeneity of this malignancy. Use of DNA microarray, real-time reverse transcription polymerase chain reaction, and tissue array immunohistochemistry methodologies makes the development of new classifications possible based on molecular profiling. The molecular classification of DLBCL may lead to the grouping of specific disease entities sharing similar biologic features, clinical behavior, and outcome. Once tested and validated, this new generation of prognostic models should become an integral part of the daily practice, providing valuable additional information to the currently existing clinically based predictive models. To accomplish these goals and to be in a position in which existing or new prognostic models can be easily tested and validated, there is a strong need to collect frozen and paraffin-embedded material that can be used for RNA extraction and construction of tissue arrays, respectively. Such materials should be gathered as an integral part of any planned study.