Absence of Kaposi's sarcoma-associated virus (human herpesvirus-8) sequences in angiosarcoma

Kaposi's sarcoma-associated virus (human herpesvirus-8 [HHV8]) sequences have been identified in both AIDS-associated and AIDS-non-associated Kaposi's sarcoma, but data relating to the detection of HHV8 sequences in angiosarcoma are variable. One study showed HHV8 sequences in 29% (7/24) of angiosarcomas, but others have not confirmed these results. We evaluated 33 angiosarcomas for HHV8 sequences to determine the frequency of this virus in angiosarcomas and its possible pathogenetic significance. Five cases of Kaposi's sarcoma from HIV-positive patients were used as positive controls. Five additional cases of Kaposi's sarcoma collected approximately 40-50 years ago were also analysed, and three were HHV8 positive. None of the angiosarcomas revealed HHV8 sequences after the standard 35 cycles of PCR. In 6 cases, nested PCR revealed the presence of HHV8 sequences. These results were not reproducible when outer primers (based on sequences outside of the earlier PCR products) were used for amplification. This suggests that the HHV8 sequences detected in 6 cases represent a low level of contamination. In contrast, HHV8 sequences were found in all Kaposi's sarcomas with well-preserved DNA after standard 35-cycle PCR amplification. These findings confirm a close association between Kaposi's sarcoma and HHV8 infection and suggest that HHV8 is not involved in the pathogenesis of angiosarcoma.