Unsilencing Endogenous Retrovirus Genes Might Contribute to Lymphomas

Retroviruses are RNA viruses that make DNA copies of themselves and integrate into the DNA of the animals that they infect. Hundreds of millions of years ago, the genomes of our mammalian predecessors became pockmarked with DNA copies of retroviral genes. About 8% of the modern human genome is composed of these ancient retroviral genes, but they apparently cannot form retroviruses. For this reason, most scientists have assumed they are just evolutionary detritus that plays no role in the pathogenesis of disease.

An international team presents evidence that, in B lymphocytes from Hodgkin lymphoma and in anaplastic large cell lymphoma cells (but not in noncancerous lymphocytes), certain retroviral genes have been turned on again. They produce …