Definition:

Hodgkin's lymphoma (HL) is one of the most frequent lymphomas in the Western world and often affects young adults. HL is subdivided into classical and nodular lymphocyte-predominant forms. About 95% of cases are classical HL, and 5% are nodular lymphocyte-predominant HL (NLPHL). A characteristic feature of HL is the rareness of the tumor cells, which are called Hodgkin's and Reed/Sternberg (HRS) cells in classical HL and lymphocytic and histiocytic (L&H) cells in NLPHL. These cells represent only about 1% of the cellular infiltrate, while the vast majority of infiltrating cells are T lymphocytes, histiocytes, eosinophilic granulocytes and plasma cells. HRS cells show constitutive activity of both the classical and alternative NF-{kappa}B signalling pathways, which is probably a major pathogenetic mechanism in Hodgkin's lymphoma. The NF-{kappa}B activity in HRS cells is probably mediated by diverse mechanisms: receptor signalling through CD40, RANK, BCMA, and TACI, genomic REL amplification, destructive mutations in IKBA and IKBE. In HL pathogenesis associated with Epstein-Barr virus infection, the activation of NF-{kappa}B is induced by viral latent membrane protein 1 (LMP1).