B-cell malignancies

The mature B-cell neoplasms include numerous subtypes of B-cell leukemias and lymphomas (BCL), as well as plasma cell neoplasms. BCL represent 80-90 % of mature lymphoid leukemias and non-Hodgkin lymphomas (NHL) in the Western world. BCL subtypes include numerous distinct diseases, with different biologies, natural histories, morphologic characteristics, immunophenotypes, genetic features, prognoses, and responses to therapy. BCL also include the majority of immunodeficiency-associated lymphomas. Accurate subclassification of BCL has been a challenge for pathologists, resulting in early application of new techniques in molecular analysis to improve diagnostic accuracy. Today, the molecular features of BCL are used to aid in rendering an accurate diagnosis, to predict prognosis, to help determine optimal therapy, and to assess for minimal residual disease (MRD) after therapy. The molecular abnormalities in BCL have commonly been evaluated for clinical purposes, including those occurring in genes coding for antigen receptor (AgR) molecules and those occurring in oncogenes and tumor suppressor genes. This chapter will discuss current molecular testing methods for BCL, as well as some of the newer methods being developed for BCL.