OBJECTIVETo study the relationship between Kaposi's sarcoma (KS) and human herpes virus 8 (HHV8; Kaposi's sarcoma-associated herpes virus), and to develop an in situ hybridization (ISH) technique effective for clinical pathological diagnosis.

METHODSPolymerase chain reaction (PCR) technique was used to synthesize a digoxigenin-labeled single stranded DNA probe specific for HHV8 open reading frame 72 cyclin D homolog gene encoded mRNA as the probe accompanying with a tyramide signal amplification system (TSA) for ISH assay. Totally 20 formalin-fixed and paraffin-embedded samples from 14 cases of KS from Danish patients were collected for HHV8 detection. In order to compare the result obtained, all of these cases were checked simultaneously using PCR technique.

RESULTSHHV8 was detected in 10 of 14 (71%) KS cases, of which 8 cases were positive for HHV8 by both ISH and PCR. In ISH, HHV8 hybridization signal was seen as a dot or patch located in the nuclei of both the neoplastic spindle cells and the endothelial cells. HHV8 was found in lesions in all the stages of KS including early patch, plaque and late nodular or tumor lesions, as well as in the primary and metastatic lesions. All the control cases showed a relevant positive or negative results.

CONCLUSIONSThe results further confirmed that there is a strong association between Kaposi's sarcoma and HHV8. The ISH technique with single stranded probe and TSA would be helpful in clinical pathological diagnosis for HHV8 infected diseases, such as KS, primary effusion lymphoma and multicentric Castleman's disease.