NPM-ALK Reverse Transcriptase-Polymerase Chain Reaction Analysis for Detection of the t(2;5) Translocation of...

The diagnosis and classification of non-Hodgkin's lymphoma (NHL) has traditionally been made based on morphologic and mununophenotypic criteria. Unfortunately, because of the diverse nature of this group of diseases, rehante solely on these criteria has frequently resulted in misdiagnosis. In addition, investigators have been limited m their ability to define biologically and clinically relevant non-Hodgkin's lymphoma subgroups using this diagnostic approach. The development of modern molecular biological techniques and their use to characterize the genetic abnormalities that are of pathogenic significance in NHL now provides an additional means to identify and to rationally subcategorize these neoplasms. The shortcomings of traditional methods of NHL diagnosis and classification have been especially evident within the morphological subset commonly referred to as the large-cell lymphomas, which comprise approx 25 and 40% of NHL m children and adults, respec tively (1). The marked cytological, immunological, and clinical heterogeneity of this group of tumors suggests that it is comprised of several biologically different neoplasms. However, morphological and immunophenotypic subclassification of the large-cell lymphomas has failed to identify a subset of tumors having a reproducibly different therapeutic response or patient survival rate. Until recently, recurrent genetic abnormalities characteristic of the large-cell lymphomas had not been identified.However, the characterization during the past 2 yr of chromosomal rearrangements mvolvmg the BCL6/LAZ3 zmc finger gene located at 3q27 (which is altered m approx 30% of these tumors [2,3]), and the cloning by our group (4) of the NPM-ALK fusion gene produced by the t(2;5) may now permrt the identrficatton of molecular genetic subtypes of largecell lymphoma that possess unique btological and/or clinical features.