A virus that infects humans without causing disease kills breast cancer cells in the laboratory. Researchers from Pennsylvania State University (Penn State) College of Medicine in the US, tested an unaltered form of adeno-associated virus type 2 (AAV2) on three different human breast cancer types representing different stages of cancer and found it targeted all of them. They hope by uncovering the pathways the virus uses to trigger cancer cell death, their work will lead to new targets for anti-cancer drugs. A paper on this work appeared recently in the journal Molecular Cancer.