A genetically modified herpes virus has been created that can block the spread of breast and ovarian cancer.
Scientists believe the virus, which has been reprogrammed so it no longer harms humans, could form the basis of a new cancer treatment.
The "oncolytic" herpes simplex virus (HSV) attacks especially aggressive tumours that have an over-active Her-2 gene.
When the modified virus was injected into mice growing human breast and ovarian tumours, it strongly inhibited the spread of cancer cells.
Lead scientist Professor Gabriella Campadelli-Fiume, from the University of Bologna in Italy, said: "We were the first to obtain a herpes virus reprogrammed to enter Her-2-positive tumour cells, unable to infect any other cell, yet preserves the full-blown killing capacity of the wild-type HSV."
The research is reported in the online journal 'Public Library of Science Pathogens'.
Meanwhile, a stroke gene has been identified that could help save lives and prevent disability. People with a mutant form of the ABO gene that determines blood group are more likely to have certain types of stroke, researchers found.
The research highlights differences between various of types of stroke, paving the way to personalised therapies.
Scientists unscrambled the DNA of 2,100 healthy volunteers and identified 23 genetic variants linked to blood clotting, one of the chief causes of strokes.
Next, they focused on the 23 variants in 4,200 stroke patients and stroke-free individuals from centres across Europe.
The research showed that a particular variant of the ABO gene was significantly associated with stroke.
The findings are published today in the journal 'Annals of Neurology'.