Background: In the Mediterranean region , Kaposi's sarcoma (KS) has a high prevalence especially in patients with AIDS. Iran is located close to the Mediterranean region and the HIV prevalence is increasing in our country . In some stages, Kaposi's sarcoma is morphologically similar to other vascular tumors. Owing to the presence of human herpesvirus 8 (HHV-8) in all cases of Kaposi's sarcoma , detection of virus DNA by PCR method can help in the identification of non-diagnostic cases. Moreover, the prevalence of HHV-8 genotypes is different in various regions of the world and in different races. There are limited studies performed on the HHV-8 genotypes in Iranian population.

Methods: Patients with Kaposi's sarcoma from 2001 to 2011 who refer to Tehran Razi Hospital were enrolled in this study. HHV-8 DNA was extracted from paraffin blocks and amplification of the virus genome was performed by PCR method . Finally, the target DNA fragment was used for sequencing and genotype determination.

Results: PCR was performed on 53 cases. In 8 cases with suspicious morphology, PCR was negative and they were excluded from study. Of remaining 45 cases, 35 had positive PCR results, 7 had negative results and 3 had low PCR product. Samples from 28 cases that had positive PCR results, which were acceptable for genotyping, were chosen for sequencing. Twenty cases had genotype C, 7 cases had genotype A and one case was negative. The results are consistent with other studies in our geographical area. No correlation was found between the different microscopic stages and HHV-8 Genotypes.

Conclusion: Since the HHV-8 is obtained in almost 100% of KS lesions and PCR s ensitivity in detection of the virus is close to 100 %, KS diagnosis can be confirmed in suspicious cases by detection of HHV-8 DNA on paraffin blocks. Moreover the prevalence of HHV-8 genotype was determined in Iran.