Oncogenic herpesviruses: viral mechanisms and modified immune responses involved in oncogenesis

Abstract

The herpesviruses EBV and KSHV are strongly associated with malignancies like Hodgkin’s lymphoma, Kaposi’s sarcoma and Burkitt’s lymphoma. Distinguishing between an associative or causative relation however is very challenging. In this review a minimal set of guidelines to assist with this distinction is extracted from various etiologic guidelines. Using these guidelines the strength of associations between EBV or KSHV and their linked malignancies is shown. Furthermore the KSHV and EBV gene expression profiles and oncogenic capacities of these genes are described in detail. Together this information is used to determine causality for EBV and KSHV in their related malignancies. However, the important role of immune evasion cannot be neglected as KSHV and EBV infection alone does not seem to be sufficient to cause cancer. The immune evasion mechanisms of EBV and KSHV viruses and their associated malignancies are discussed and further research is proposed to obtain more insight into the molecular mechanisms changed by this immune suppression. A better understanding of the role of immune suppression in the cause of malignancies can contribute to develop specific treatments of these EBV- and KSHV-associated tumors and to determine possible cancer prevention strategies.