NEET BIOLOGY

Detailed explanation-1: -An oncovirus or oncogenic virus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s, when the term “oncornaviruses” was used to denote their RNA virus origin.

Detailed explanation-2: -Although a number of oncogenic retroviruses are capable of inducing tumors in animals, their relevance to human disease is mainly their role in the discovery of oncogenes. Oncogenic DNA viruses, in contrast, are an etiological factor in a significant portion of human cancers.

Detailed explanation-3: -Oncogenic DNA viruses include EBV, hepatitis B virus (HBV), human papillomavirus (HPV), human herpesvirus-8 (HHV-8), and Merkel cell polyomavirus (MCPyV). Oncogenic RNA viruses include, hepatitis C virus (HCV) and human T-cell lymphotropic virus-1 (HTLV-1).

Detailed explanation-4: -Papillomaviruses. The papillomaviruses are small DNA viruses (genomes of approximately 8 kb) that induce both benign and malignant tumors in humans and a variety of other animal species. Approximately 60 different types of human papillomaviruses, which infect epithelial cells of several tissues, have been identified.