High Expression of the bcl-x Gene in Reed-Sternberg Cells of Hodgkin's Disease

The expression of bcl-x protein, a bcl-2-related protein present in cortical thymocytes, activated lymphocytes, and plasma cells of reactive lymph nodes, was investigated in 44 cases of Hodgkin's disease (HD) in parallel with bcl-2 and Epstein-Barr virus (EBV) status. Eighty-six percent of the cases were positive for bcl-x, among them 27% with a strong signal in more than 75% of the Reed-Sternberg cells. Positivity for bcl-x was found in, respectively, 100% and 92% of the nodular sclerosis and mixed cellularity subtypes, although 4 cases of lymphocyte predominance subtype were negative. This finding was in contrast with the weaker positivity for bcl-2 staining in 44% of the cases. EBV small RNAs were detected in 43% of the cases by using in situ hybridization. Of interest, 100% of the EBV-positive samples were positive for bcl-x, whereas only 38% of these cases were bcl-2 positive. Our findings show that the bcl-x gene expression is high in HD, suggesting that bcl-x may have a role in the pathogenesis of at least some cases of HD via apoptosis regulation.