Part I: Hodgkin's lymphoma--molecular biology of Hodgkin and Reed-Sternberg cells.

Classic Hodgkin's lymphoma is characterised by Hodgkin and Reed-Sternberg cells and in most cases are derived from germinal-centre B cells. Despite progress in basic research showing the natural precursor cells of Hodgkin's lymphoma, most key questions still remain unanswered. Among these are the basic transforming events, the involvement of oncogenic viruses, the mechanisms enabling Hodgkin and Reed Sternberg cells to resist apoptosis in the germinal centre, and the molecular causes of their characteristic phenotype. Beyond the disclosure of these issues, the detection of changes in gene expression, gene mutations, and chromosomal imbalances specific of Hodgkin's lymphoma are central to recent research that may allow one a better understanding of the natural history of this type of lymphoma.