RNA-tumor viruses, also known as retroviruses, are a group of viruses that can cause cancer in humans and animals. These viruses are characterized by their unique RNA genome, which can be reversed-transcribed into DNA and integrated into the host cell's genome. Some synonyms for RNA-tumor viruses include oncogenic retroviruses, carcinogenic retroviruses, and tumorigenic retroviruses. These terms highlight the fact that these viruses have the potential to cause cancer in their hosts. Other synonyms for RNA-tumor viruses may include specific virus names such as human T-lymphotropic virus (HTLV), feline leukemia virus (FeLV), and avian sarcoma virus (ASV). Understanding these synonyms is crucial to accurately discuss research and studies related to retroviruses and cancer.