Relationship of intratumoural protein expression patterns to age and Epstein-Barr virus status in classical Hodgkin lymphoma

In Western countries, the age distribution of Hodgkin lymphoma (HL) follows a characteristic bimodal curve showing an early and a late peak at approximately 35 and 70 yr, respectively. Furthermore, the presence of latent Epstein‐Barr virus (EBV) genome in the Hodgkin Reed–Sternberg cells, the tumour cell population of classical HL (cHL), has been found to have adverse prognostic impact in elderly, but not in younger cHL patients. We have characterised the protein expression in tumour tissue samples from younger (≤55 yr) and elderly (>55 yr) cHL patients and correlated the findings with EBV status. Differentially expressed proteins according to patients’ age as well as tumoural EBV status belonged to different biological functional domains, such as apoptosis, cytoskeletal organisation, response to oxygen levels and regulation of catabolic/metabolic processes. The differential expression of selected proteins, cytosolic aminopeptidase, heterogeneous nuclear ribonucleoprotein K, serotransferrin and alpha‐1‐antitrypsin was further validated by Western blot analysis. Discovery‐based proteomics characterising biological features distinctive for subsets of cHL patients may be useful for the identification of novel biomarkers with potential therapeutic relevance. An evaluation of the prognostic impact of protein expression pattern in general and individually expressed proteins in particular is warranted.