Israel Medical Association Journal

The ubiquitin-proteasome pathway has a central role in selective degradation of intracellular proteins. Among the key proteins degraded by the system are those involved in the control of inflammation, cell cycle regulation and gene expression. With numerous important cellular pathways affected, derangements in the ubiquitin system were shown to result in a variety of human diseases including malignancies, neurodegenerative diseases and hereditary syndromes, and proteasome inhibition was implicated as a potential treatment for cancer and inflammatory conditions. Two proteasome inhibitors are currently under clinical evaluation for multiple myeloma and acute ischemic stroke. The ubiquitin system also has an important function in the immune and inflammatory response. It is involved in antigen processing and presentation to cytotoxic T cells, and the activation of nuclear factor-kappa B – the central transcription factor of the immune system. Since the proteasome is the central source of antigenic peptides that are presented to the immune system, some viruses, such as the Epstein-Barr virus, developed escape mechanisms that manipulate the ubiquitin-proteasome system in order to persist in the infected host. Understanding the mechanisms underlying the production of viral antigens by the ubiquitin-proteasome system may have therapeutic applications such as future development of vaccines.

Background: A previous study on Hodgkin's lymphoma in southern Israel found that Bedouin patients had an increased rate of Epstein-Barr virus expression in their tumor cells.

Objectives: To determine the influence of the patients' communities on the pattern of disease in HL.

Methods: We compared the clinical features, demographic data, stage at diagnosis, treatment modality and outcome, as well as laboratory findings, in four community-based subgroups. These groups comprised kibbutz residents (n=11), Bedouin (n=19), new immigrants from the former USSR (n=22), and town-dwellers (n=82).

Results: The Bedouin patients differed significantly from the new immigrants and town-dwellers, particularly regarding the rate of EBV sequences in the tumor tissues, and a poorer response to treatment. The kibbutz patients did not differ significantly from the other populations regarding most of the parameters studied, but showed an intermediate expression of EBV antigens compared to Bedouin patients and the rest of the cohort.

Conclusions: This study indicates that HL may behave differently in different population groups in a given geographic area. Notably, the Bedouin patients showed markedly different clinical and biological patterns of this malignancy. 

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HL= Hodgkin's lymphoma

EBV= Epstein-Barr virus