EXPRESSION OF P53 AND MDM-2 PROTEINS IN HODGKINS-DISEASE - ABSENCE OFCORRELATION WITH THE PRESENCE OF EPSTEIN-BARR-VIRUS

The expression of p53 and mdm-2 proteins was analysed in parrafin sect ions from 39 cases of Hodgkin's disease (HD) and compared to the prese nce of Epstein-Barr Virus (EBV). P53 protein was found in Hodgkin and Reed-Sternberg (HRS) cells in 12/39 cases. Mdm-2 protein was Sound in HRS cells in 10/39 cases. EBV-encoded EBER1-2 mRNAs and LMP-1 protein expression were found in HRS cells in 16/39 cases. In view of the LMP- 1 oncogenic potential in vitro, these findings suggest that EBV may be involved in the pathogenesis of a proportion of HD cases. The coexpre ssion of mdm-2 and p53 proteins was found in HRS cells in 10 cases, wh ereas in 27 cases neither was identified and in 2 cases there was no c oexpression of mdm-2/p53. The simultaneous p53/mdm-2 protein expressio n, in view of previous findings which showed that most cases of HD dis play no p53 gene mutations, suggests that mdm-2 protein expression may be one of the factors responsible for the stabilisation of p53 protei n in these cases. This could be important, in the pathogenesis of thes e cases of HD, since mdm-2 may deregulate the p53 dependent growth sup pressive pathway Mdm-2-/p53+ protein expression may reflect the stabil isation of p53 protein by proteins other than mdm-2, mutations in the p53 gene making it unable to activate mdm-2, or the deregulation of th e mdm-2 gene. No relationship was found between the presence of EBV an d the expression of p53 and/or mdm-2 proteins.