Scientists have developed a common cold virus that destroys cancer cells in mice without harming healthy ones.
They modified a common bug called on adenovirus, which typically causes chest infections, so that it delivered vital genetic therapy to tumours without poisoning the liver, reports The Scotsman.
The virus was allowed to keep enough of its genetic "signature" to trigger an immune response, which safely eradicated it after the job was done.
The work was reported in the journal PLoS Pathogens.
Lead author Professor Leonard Seymour, of Oxford University, said: "The approach we developed is easy to use and flexible.
"It may help in the development of future therapeutic viruses that are specific to certain disease sites."