Expression of the tumour necrosis factor receptor-associated factors 1 and 2 in Hodgkin's disease

The tumour necrosis factor receptor-associated factors (TRAFs) 1 and 2 participate in the signal transduction of various members of the tumour necrosis factor receptor (TNFR) family, including TNFR1, TNFR2, CD40, CD30, and the Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP1). Previous in situ hybridization studies have demonstrated TRAF1 transcripts in the malignant cells of the majority of Hodgkin's disease (HD) tumours, where the expression of TRAF1 was higher in EBV-associated tumours than in their EBV-negative counterparts. In order to determine whether TRAF1 and also TRAF2 were expressed at the protein level in HD and whether there was any relationship to EBV status, immunohistochemistry has been used to detect these proteins in a series of HD specimens. TRAF1 protein was detected more frequently in Hodgkin/Reed-Sternberg (HRS) cells from EBV-positive tumours than in their EBV-negative counterparts. This difference was statistically significant (p=0.01). In contrast, TRAF2 expression by HRS cells appeared to be independent of EBV status. Using a sequential labelling approach, co-localization of LMP1 with either TRAF1 or TRAF2 was also demonstrated in HRS cells from EBV-positive tumours.