MOST OF CD30(-CELL LYMPHOMA OF B-CELL TYPE SHOW A SOMATIC MUTATION INTHE IGH V REGION GENES() ANAPLASTIC LARGE)

Relationship and histogenesis of Hodgkin's disease (HD) and anaplastic large cell lymphoma (ALCL) still remain unclear. Recently, Reed-Stern berg cells or Hodgkin cells in HD with B cell phenotype (B-HD) are con sidered to originate from germinal center B cells, ALCLs of B cell phe notype (B-ALCL) are involved in diffuse large B cell lymphoma (DLBCL) as anaplastic variant, but an origin of tumor cells of B-ALCL has not been elucidated. We have therefore investigated somatic mutation of th e tg heavy chain (IgH) genes among 17 cases of B-ALCL to clarify wheth er there is a difference in characteristic and origin of tumor cells b etween B-ALCL, B-HD and DLBCL. Amplificates of IgH variable (V) region of 10 cases by the polymerase chain reaction method were sequenced an d compared with reported germ line configurations. Nine cases (90%) wi th heavily somatic mutations were found. A case with an out-of-frame r earrangement and a case with 9 base pairs insertion were included. The mutation pattern revealed the tumor cells were selected for antibody expression and discriminated from B-HD. These findings suggest the tum or cells of B-ALCL are derived from germinal center or postgerminal ce nter (memory and effector) B cells and an origin of B-ALCL is not diff erent from DLBCL.