Abstract
Lymphoproliferative diseases include many different disease entities with distinct cells of origin, pathologies, risk factor profiles, and prognoses. Although lymphomas are grouped traditionally into non-Hodgkin and Hodgkin lymphomas, the WHO classification today separates lymphomas into three main groups, B-cell, T-/NK-cell and Hodgkin lymphomas, where each group includes multiple subtypes. For instance, B-cell lymphomas comprise entities such as follicular lymphomas, diffuse large B-cell lymphomas, chronic lymphocytic leukemia, and lymphoplasmacytic lymphoma/Waldenström macroglobulinemia. The causes of lymphomas are mostly unknown; however, known risk factors include autoimmunity, infections, and heredity. This chapter will focus on familiality, define basic concepts in lymphomagenesis, and discuss important genetic events in specific lymphomas.