How infections with non-retroviral RNA viruses may be involved in the development of neoplasia.

There have been reports of associations of infections with non-retroviral RNA viruses and tumour development. A hypothesis is proposed as to how non-retroviral RNA viruses may play a role in the development of neoplasia. It is based on a recent report of the detection of complementary DNA (cDNA) of the RNA virus lymphocytic choriomeningitis virus in mouse and hamster cells. This lends credence to the claim made in 1975 of the detection of cDNA copies of genomic DNA of three non-retroviral RNA viruses integrated into the DNA of host cells. Briefly, the hypothesis proposes that at least one cDNA fragment of a non-retroviral RNA virus is synthesized and integrated into the genome of the host cell in a way that could lead or contribute to tumour development. General approaches for testing the hypothesis are outlined.