Further confirmation of the association of human herpesvirus 8 with Kaposi's sarcoma.

Recently, a new herpesvirus-like DNA sequence named Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) has been isolated from almost all cases of Kaposi's sarcoma (KS). It has not been found in most benign and malignant cutaneous hemangioproliferative disorders other than KS. To further verify the specificity of the association of this new viral DNA with KS, we examined in total 42 cases of vascular neoplasms of endothelial derivation using nested polymerase chain reaction (PCR) for the presence of a 233-bp segment of this KSHV/HHV8 on paraffin-embedded specimens. In our investigation, we added an additional step to conventional PCR protocol that uses UV light to pretreat all the PCR regeants except Taq DNA polymerase and the target DNA to eliminate the false positives caused by trace contamination. All 15 cases of typical KS, both AIDS and non-AIDS related, as well as 4 cases of atypical vascular tumors suspicious of KS, were positive for this KSHV/HHV8 DNA sequence. The remaining 23 cases of hemangioproliferative disorders other than KS, including angiosarcoma, capillary hemangioma, angiolymphoid hyperplasia with eosinophilia, epithelioid hemangioma, histiocytoid hemangioma, hemangioendothelioma, and microvenous hemangioma, were negative for HHV8. These results confirm the previous observation that KSHV/HHV8 is specific for KS within hemangioproliferative cutaneous disorders, and PCR for detection of KSHV/HHV8 might be used as an additional diagnostic tool in distinguishing KS.