Several studies have detected Simian virus 40 (SV40) deoxyribonucleic acid sequences in human tumortissues, including lymphomas, mainlyby the polymerase chain reaction, but these data were not confirmed by subsequent investigations. Regional differences in the distribution of the SV40 and/or technical difficulties have been taken into account to explain these divergent results, but because only a few such studies dealt with the expression of SV40 proteins in tumor tissues, we investigated the expression of the SV40 large T antigen in human lymphomas by immunohistochemistry. Tissue microarrays containing Non-Hodgkin'slymphomas and Hodgkin's-lymphomas were constructed utilizing archival samples encompassing the years 1974-2001 from Italian, Swiss and Austrian patients. Expression of the SV40 large T antigen was analysed by highly specific and sensitive immunohistochemistry using a mouse monoclonal antibody. Protein expression of the large T antigen was not detected in 655 Non-Hodgkin's-lymphomas or in 337 Hodgkin'slymphomas. The results suggest the absence of an association between SV40 large T antigen and human lymphomas. J. Med. Virol. 80:1112-1115, 2008. © 2008 Wiley-Liss, Inc.