A flurry of new studies suggest scientists are finally figuring out how to harness the immune system to attack a ruthless form of brain cancer.

While preliminary, the results offer hope that progress is possible against glioblastoma, the terrible form of cancer that so swiftly took the lives of Arizona Sen. John McCain and U.S. President Joe Biden’s son Beau.

But the studies, while astonishing, are small. What’s needed next is an urgent effort to prove the effect can allow people to live longer and better — and to explore how it can be extended into other types of cancer.