The Viral Etiology of Skin Cancer

Abstract

The concept that viruses may be etiological agents of cancers is as old as the discovery of viruses themselves. In 1908, 3 years before Peyton Rous was passaging what later became to be known as Rous Sarcoma Virus in chickens, two Danish scientists, Ellerman and Bang, were characterizing a transmissible filtrate that reproducibly caused leukemia in chickens. These findings were received with harsh skepticism, and the scientific community did not universally accept the concept that tumors could be caused by transmissible agents. Richard Shope, a colleague of Peyton Rous at the Rockefeller Institute, identified an infectious agent that infected cottontail rabbits. It caused cutaneous papillomas that could grow to be quite large and which may be the basis of sightings of the mystical and ravenous ‘‘Jackelope’’ of southwestern American lore. Shope later collaborated with Rous to demonstrate that exposure of these papillomas to coal tar or infection of a host that does not support viral replication caused malignant progression to skin cancers. This infectious agent, the cottontail rabbit papillomavirus or Sylvilagus floridanus Papillomavirus 1, was the first virus linked to a cancer in a mammalian host (Javier and Butel, 2008; Moore and Chang, 2010) (Figure 1).