A new startlingly effective injection revitalizes and boosts the body’s own cancer defenses.

“T cells” play a vital role in our immune system. Typically, it is those lymphocytes that recognize and target cancer when it appears in the body. But as a tumor grows, it begins to suppress the function of those cells, rendering the body defenseless against the deadly, creeping mass.

The immunotherapy injection simply reactivates those cells, stimulating them to ignore cancer’s oppression and fight back. Rather than the less effective — and substantially more difficult — process of CAR T-cell therapy, in which cells are removed from the body and then engineered to fight the cancer before being returned, the two agents in the injection combine to do all the necessary work “in-house,” so to speak.

Stanford University School of Medicine Professor of Oncology Dr. Ronald Levy, the senior author of the Science Translational Medicine study, said that the treatment is “attacking specific targets without having to identify exactly what proteins the T cells are recognizing.” Not only that, but the rejuvenated T-cells are even eliminating metastasized tumors that have spread to other parts of the body.

Still, many questions still need to be answered before this potential cancer eradicator changes the world. Northwell Health Cancer Institute’s Regional Director of Breast Surgery, Dr. Alice Police, said that while the promise of the treatment is “exciting,” doctors have “been able to cure a lot of cancers in mice for a long time.”

Unfortunately, those results don’t always translate to humans. “We’ve [gone] one step further down the road,” Police said, “but it’s [still] a long way to go.”

For the neatly 1.7 million people expected to be diagnosed with cancer in 2018 alone — as well as for the many millions already suffering around the globe — it is a vital ray of hope.