Usefulness of immunohistochemistry in identification of prognostically important subgroups (GCB and ABC) in a heterogeneous group of diffuse large B-cell lymphomas--a review article.

Although diffuse large B cell lymphomas (DLBCL) are considered in the WHO classification a specific histopathological type, their diversity in the clinical features, morphology and molecular aberrations strongly suggest that these tumors represent a heterogeneous group of neoplasms rather than a single clinicopathological entity. There have been various approaches to differentiate between separate nosological entities within DLBCLs based on various methods, such as the microarray technique or immunohistochemistry. Although it has been proven that gene expression profiling using cDNA microarrays could identify prognostically important subgroup of DLBCL: germinal center B-cell (GCB)-like DLBCL and activated B-cell (ABC)-like DLBCL, this method is impractical as a clinical tool. Therefore, investigators have started using immunohistochemistry in their studies. Employing various immunohistochemical antibodies, such as CD10, CD138, anti-Bcl-2, anti-Bcl-6, MUM1 and anti-p53, several groups have aimed at subclassifying DLBCL into the GCB and ABC subgroups with comparable differences in clinical behavior. This review summarizes these data and indicates their impact on DLBCL classification.