Tiny phages that usually infect microbes could fight cancer Science Photo Library/Getty

People with incurable melanomas and brain or breast cancers are to get injections of tumour-fighting viruses.

The trial will test the safety of a virus that has been engineered to shrink tumours – an approach that holds promise for a range of cancers, including deadly brain tumours.

The idea of using viruses to kill cancers goes back more than a century, inspired by anecdotal reports of some people with viral infections being cured of malignancies. But turning viruses that can infect and kill human cells into a safe and effective …