Commonly used viruses include adenoviruses, retroviruses, and various bacteriophages. Popular virus vectors are developed from retroviruses or adenoviruses. Many vertebrate genes were formed from retroviruses and LTR retrotransposons. Reverse transcriptase is an enzyme that retroviruses, including HIV, utilize to replicate themselves. In vertebrates EVEs derived from retroviruses (endogenous retroviruses) are relatively common. Duesberg disputes the importance of oncogenes and retroviruses in cancer. APOBEC family can also protect against the infection of RNA retroviruses and retrotransposons. A certain type of latency could be ascribed to the endogenous retroviruses. It is very commonly used in biology for protein expression and production of recombinant retroviruses. The characteristics of retrotransposons are similar to retroviruses, such as HIV. The discovery of Wnt signaling was influenced by research on oncogenic (cancer-causing) retroviruses. Another term for RNA viruses that explicitly excludes retroviruses is ribovirus. They are present in only eukaryotes but share features with retroviruses such as HIV. Many antiviral drugs are designed to treat infections by retroviruses, including HIV. Human endogenous retroviruses (HERVs) have been reported in MS for several years.