The team hid cancer killing viruses inside the immune system in order to sneak them into a tumour.
Once inside, a study in the journal Cancer Research showed, tens of thousands of viruses were released to kill the cancerous cells.
Experts labelled the study "exciting," but human tests are still needed.
Using viruses to destroy rapidly growing tumours is an emerging field in cancer therapy, however one of the challenges is getting the viruses deep inside the tumour where they can do the damage.
