Epstein–Barr virus (EBV) encodes 49 microRNAs (miRNAs) in the BART and BHRF1 regions of its genome. Although expression profiles of EBV‐encoded miRNAs have been reported for EBV‐positive cell lines and nasopharyngeal carcinoma, to date there is little information about total miRNA expression, including cellular and viral miRNAs, in the primary tumors of EBV‐associated B‐lymphoproliferative disorders. In this study, next‐generation sequencing and quantitative real‐time reverse transcription‐PCR were used to determine the expression profiles of miRNAs in EBV‐infected cell lines and EBV‐associated B‐cell lymphomas, including AIDS‐related diffuse large B‐cell lymphoma (DLBCL), pyothorax‐associated lymphoma, methotrexate‐associated lymphoproliferative disorder, EBV‐positive DLBCL of the elderly, and Hodgkin lymphoma. Next‐generation sequencing revealed that EBV‐encoded miRNAs accounted for up to 34% of total annotated miRNAs in these cases. Expression of three miR‐BHRF1s was significantly higher in AIDS‐related DLBCL and pyothorax‐associated lymphoma compared with methotrexate‐associated lymphoproliferative disorder and EBV‐positive DLBCL of the elderly, suggesting the association of miR‐BHRF1s expression with latency III EBV infection. Heat map/clustering analysis of expression of all miRNAs, including cellular and EBV miRNAs, by next‐generation sequencing demonstrated that each EBV tumor, except methotrexate‐associated lymphoproliferative disorder, formed an isolated cluster. Principal component analysis based on the EBV‐encoded miRNA expression showed that each EBV tumor formed a distinguished cluster, but AIDS‐related DLBCL and pyothorax‐associated lymphoma formed larger clusters than other tumors. These data suggest that expression of miRNAs, including EBV‐encoded miRNAs, is associated with the tumor type and status of virus infection in these tumors.

Kaposi's sarcoma-associated herpesvirus (KSHV) is related causally to Kaposi's sarcoma, primary effusion lymphoma, and a subset of cases of multicentric Castleman's disease. As the numbers of acquired immunodeficiency syndrome (AIDS) patients have increased, KSHV-associated diseases have also increased in Japan. Sporadic cases of classic Kaposi's sarcoma have also been reported in Japan. In the present study, the clinicopathological characteristics of 75 samples, comprising 68 cases of Kaposi's sarcoma, 5 cases of primary effusion lymphoma, and 5 cases of multicentric Castleman's disease were investigated. All of these cases were positive for KSHV by immunohistochemistry or PCR analysis. All fifty-two of the AIDS-associated Kaposi's sarcoma cases were males, whereas 7 of the 13 non-AIDS-associated Kaposi's sarcoma cases were females. The mean age of patients with AIDS-associated Kaposi's sarcoma or primary effusion lymphoma was 46 years, whereas the mean age of patients with non-AIDS-associated Kaposi's sarcoma or primary effusion lymphoma was 71.8 and 97.5, respectively. KSHV genotypes were determined based on the sequence of variable region 1 in the K1 gene. Genotypes A and C of KSHV were detected in both AIDS- and non-AIDS-associated Kaposi's sarcoma. Genotype A was detected more frequently in AIDS-associated cases than non-AIDS-associated cases, suggesting that genotype C is broadly distributed in Japan, and genotype A spreads among AIDS patients. Genotype D was detected only in non-AIDS-associated Kaposi's sarcoma. These data confirmed the difference between AIDS- and non-AIDS-associated KSHV diseases with regard to age of onset, gender, and genotypes in Japan. J. Med. Virol. 82:400-406, 2010. (c) 2010 Wiley-Liss, Inc.

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