The role of CD30 in the pathogenesis of haematopoietic malignancies.

CD30, a member of the tumour necrosis factor receptor superfamily, is overexpressed by malignant cells of Hodgkin's lymphoma and by anaplastic large cell lymphoma. CD30 overexpression has been attributed, at least in part, to constitutive expression of JunB, a transcription factor belonging to the AP-1 family that binds to the CD30 promoter. Overexpression of CD30 in Hodgkin's lymphoma cells is thought to result in ligand-independent signaling, leading to activation of nuclear factor-kappaB and survival of the malignant cells. In anaplastic large cell lymphoma, CD30 triggering induces growth arrest and, under certain circumstances, cell death. Finally, transmembrane signalling by CD30 might be regulated by a soluble form of CD30 that is released by proteolytic cleavage of membrane-anchored CD30.