Kaposi’s sarcoma-associated herpesvirus (KSHV) is the eighth human herpesvirus. This virus causesKaposi’s sarcoma, a cancer commonly occurring in AIDS patients, as well as primary effusion lymphoma and some types of multicentric Castleman’s disease. It is one of seven currently known human cancer viruses, or oncoviruses.
Structure and Genome
KSHV is a herpesvirus, and is a large double-stranded DNA virus with a protein covering that packages its nucleic acids, called the capsid, which is then surrounded by an amorphous protein layer called the tegument, and finally enclosed in a lipid envelope derived in part from the cell membrane. KSHV has a genome which is approximately 165,000 nucleic acid bases in length. It is a rhadinovirus, and is remarkable since it has stolen numerous genes from host cells including genes that encode for complement-binding protein, IL-6, BCL-2, cyclin-D, a G protein-coupled receptor, interferon regulatory factor and Flice inhibitory protein (FLIP), as well as DNA synthesis proteins including dihydrofolate reductase, thymidine kinase, thymidylate synthetase, DNA polymerase and many others.
Kaposi’s sarcoma was first described in the 19th century as a rare skin cancer that effected elderly men in the Maditteranean region. In 1994 it was discovered that the tumor cells contain the DNA of a new herpesvirus. The virus was subsequently isolated and was named Kaposi’s sarcoma-associated herpesvirus (KSHV).
It is transmitted through sexsual contact and via organ transplant. Healthy individuals can be infected with the virus and show no signs or symptoms, due to the immune system’s ability to keep the infection in check. Kaposi’s sarcoma occurs when someone who has been infected with KSHV becomes immunocompromised due to AIDS, medical treatment or very rarely aging.
Its tumor cells are derived from endothelial cells. Two other human cancers linking with KSHV is : primary effusion lymphomas and Multicentric Castleman’s disease. Both are tumor derived from B cells,