What's new in the molecular pathology of small b-cell lymphomas: A critical review.

The increasing availability of high-throughput sequencing techniques has dramatically increased our knowledge about the molecular landscape of lymphoid malignancies and expanded the indications for molecular studies in diagnostic hematopathology. Although lymphoma diagnosis still requires careful integration of clinical, morphological, phenotypic, and in some cases molecular features, genetic profiling has had a profound impact on the evolution of lymphoma classification. For small B-cell lymphomas, recurrent alterations such as translocations involving the IGH locus have been central for defining some entities. However, recent large-scale studies have not only highlighted the complexity of genetic alterations in small B-cell lymphomas, but also identified pathogenetic mechanisms, prognostic alterations, and therapeutically targetable pathways. Furthermore, genetic profiling allows for a better characterization of entities lacking defining phenotypic and molecular features and can provide additional diagnostic support in difficult cases. In this review, the current knowledge about the genetics of small B-cell lymphomas is summarized, with a focus on alterations of diagnostic, prognostic, or therapeutic relevance.