P53 expression in Reed-Sternberg cells does not correlate with gene mutations in Hodgkin's disease

Immunohistochemically detectable p53 protein expression is common in the Reed-Sternberg and Hodgkin's (RS-H) cells of Hodgkin's disease, but p53 gene mutations have only rarely been identified. The authors found p53 expression in RS-H cells in 16 of 30 cases of Hodgkin's disease (53%), with the percentage of RS-H positive cells ranging from 4% to 85%. In 12 of 30 cases (40%), at least 10% of the RS-H cells were positive for p53. p53 gene mutations were detected in only two cases (7%) using a single-stranded conformational polymorphism assay with a detection sensitivity of between 1% and 5%. The cellular protein, mdm-2, which can stabilize and functionally inactivate wild-type p53 protein, was expressed in RS-H cells in most of these cases (86%). However, neither case with a p53 gene mutation expressed mdm-2 (P < .005). The two cases with p53 gene mutations had a higher mean proliferative index than cases without detectable mutations (90% versus 72%; P < .02). p53 expression in RS-H cells may be related to concurrent mdm-2 protein expression and a p53-positive, mdm-2-negative immunophenotype may be predictive of gene mutations in RS-H cells.