OBJECTIVE: To determine whether Epstein-Barr virus (EBV) infection is related to renal cell carcinoma (RCC) tissues. MATERIALS AND METHODS: We investigated EBV infection and its genotypes in 73 cases of different types of RCC and 18 of non-neoplastic kidney. EBV infection and its genotypes were determined by EBV-encoded RNAs in situ hybridization (EBER-ISH) and polymerase chain reactions for EBV-encoded nuclear antigen 1 (EBNA-1) and EBNA-3C. The immunophenotype and EBV status of the EBV-infected cells were examined by double-labelling of EBER-ISH and/or immunohistochemistry for lymphoid cell markers, EBV proteins, and CD21. RESULTS: EBER-ISH signals were detected in five of 73 RCC tissues (6.8%), but in none of 18 non-neoplastic kidneys. Interestingly, EBER-ISH was positive only in five of the 10 sarcomatoid RCCs, and of these, four also showed amplification of EBNA-1. EBV was located exclusively in the tumour-infiltrating B lymphocytes of sarcomatoid RCCs. The genotype of EBV was determined as type 1. A few EBV-infected B cells expressed BZLF1 (an EBV immediate-early gene product) while none expressed EBNA-2 or latent membrane protein 1. This indicates that the B cells are of EBV latency type I, often replicating EBV. EBV infection did not affect the survival rates of patients with sarcomatoid RCC (P = 0.635, Kaplan-Meier analysis, log-rank test). CONCLUSION: EBV is present only in tumour-infiltrating B lymphocytes of sarcomatoid RCCs. The present study suggests that sarcomatoid RCC modulates a function of EBV-specific T cells controlling EBV replication, or stimulates differentiation of memory B cells into plasma cells.
- Epstein-Barr virus infections
- Renal cell carcinoma
- Tumour-infiltrating lymphocytes
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