This scenario is particularly intriguing for the pathogenesis of cHL arising in HIV-infected patients, which, for still obscure reasons, is invariably EBV-associated with LMP-1 expression in HRS cells.
These methods allowed us to identify the EBV-encoded oncoprotein LMP1 as a key element in the formation of Hodgkin (H-cell) and multinucleated Reed-Sternberg cells (RS-cell), the diagnostic tumor cell of classical Hodgkin's lymphoma (cHL).
In contrast to EBV(+) PTLD which expresses the immunodominant EBV latency III EBNA3A/B/C proteins, EBV(+) cHL is restricted to the subdominant EBNA1/LMP1/LMP2 proteins.
All ptHL expressed CD15, CD30 and LMP-1 of EBV; the B-cell markers BOB-1, Oct2, CD79a and CD20 were more commonly expressed in ptHL versus cHL (100%, 86%, 50% and 38% in ptHL compared to 6%, 14%, 10% and 33% in cHL, respectively); all ptHL expressed phosphoinositide 3-kinase (PI3K) versus 81% of cHL; 2/6 (33%) ptHL displayed gains at 9p24 that were similar to cHL (32%).
In the current study, the presence of EBV was determined by PCR of the 3' end of the LMP-1 gene and EBNA-3C gene in whole tissue and, consecutively, in isolated cells from 26 cases of cHL: 10 HIV-positive and 16 sporadic cHL cases.
In a previous study, we found a high frequency of dual LMP-1 variant (concurrent presence of deleted and nondeleted variants) in cHL from whole-tissue sections.
Direct comparison of Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) expression in Hodgkin's and Reed-Sternberg (HRS) cells on conventional full sections with the corresponding duplicate/triplicate tumour cores on the TMA showed a concordance of 100%, indicating that cHL-TMA is a reliable and representative method for evaluating gene expression profiles in situ.