Eons ago, a retrovirus hijacked a gene from a chicken cell and enclosed it within its own genome. The captured gene was not idle, however: it gave the renegade virus the ability to cause tumors in chickens with amazing rapidity. The virus is the Rous sarcoma virus, the gene in the virus is called v-src, and the cellular gene is c-src. These discoveries shifted the tectonic plates of cancer research, thereby opening a new continent for exploration. The subsequent finding that v-src is a tyrosine kinase run wild substantiated the theory that cancer can originate from an unregulated cellular . . .