Anti-Cancer Virus is being developed in what researchers have labelled a medical first.

The study of an engineered virus, injected into the blood, can selectively target cancer cells throughout the body shows a lot of promise.

In a small trial on 23 patients, the virus actually attacked only tumors, leaving the healthy tissue alone, according to the Journal Nature. But they have needed to be injected directly into tumors in order to evade the immune system.

Researchers said the findings could one day become therapeutic and hopefully put an end to the most dreaded disease that’s been killing millions around the world annually.