Adeno-associated virus type 2 (AAV2) is a virus that regularly infects humans but causes no disease. Past studies by the same researchers show that it promotes tumor cell death in cervical cancer cells infected with human papillomavirus. Researchers used an unaltered, naturally occurring version of AAV2 on human breast cancer cells.

“Breast cancer is the most prevalent cancer in the world and is the leading cause of cancer-related death in women,” said Samina Alam, research associate in microbiology and immunology. “It is also complex to treat.”
…
“We can see the virus is killing the cancer cells, but how is it doing it?” Alam said. “If we can determine which viral genes are being used, we may be able to introduce those genes into a therapeutic. If we can determine which pathways the virus is triggering, we can then screen new drugs that target those pathways. Or we may simply be able to use the virus itself.”
…
AAV2 does not affect healthy cells. However, if AAV2 were used in humans, the potential exists that the body’s immune system would fight to remove it from the body. Therefore, by learning how AAV2 targets the death pathways, researchers potentially can find ways to treat the cancer without using the actual virus.

In ongoing studies, the Penn State researchers also have shown AAV2 can kill cells derived from prostate cancer, mesothelioma, squamous cell carcinoma, and melanoma. A fourth line of breast cancer cells — representing the most aggressive form of the disease — also was studied in a mouse breast tumor model, followed by treatment with AAV2. Preliminary results show the destruction of the tumors in the mice, and researchers will report the findings of those mouse studies soon.