Randy D. Gascoyne, MD, FRCPC

In this issue of ONCOLOGY,Rosenwald describes in detail thecurrent state of gene expressionprofiling and its role in the classificationand prediction of outcome in lymphoidmalignancies. Since the firstpublication describing the use of geneexpression signatures to predict outcomein diffuse large B-cell lymphoma(DLBCL), a few subsequent papershave appeared, detailing comprehensivefindings in other lymphoma subtypes.[1-4] Together these works bringclarity to the molecular taxonomyof the non-Hodgkin's lymphomas(NHL). Insights gleaned from thesestudies not only provide an improvedunderstanding of the biology of thesetumors, but have also led to a significantimprovement in our ability to assignrisk for individual patients withlymphoma.[2]

Successful therapy for most of the non-Hodgkin’s lymphomas requires an accurate pathologic diagnosis. Routine morphologic examination of excisional biopsies from nodal or extranodal sites provides the cornerstone for establishing a definitive diagnosis. The list of ancillary studies, however, used to complement these routine approaches is increasing both in number and complexity. Proper use of these diagnostic tools can be of great help in arriving at the correct diagnosis in difficult cases. Fine-needle aspiration and needle-core biopsies have a role in lymphoma staging and in the assessment of recurrent disease, but are limited as primary diagnostic tests. This review will focus on the standard approaches used to establish a diagnosis of malignant lymphoma, and the clinical utility of immunophenotypic, molecular genetic, and cytogenetic studies in providing useful data for diagnosis. The standard practice of synthesizing all of the data from multiparameter analysis to arrive at a diagnosis in difficult cases will be emphasized. [ONCOLOGY 12(Suppl 8):11-16, 1998]