The approach is called a cancer vaccine, although it treats the disease rather than prevents it.

Experimental vaccines against three other cancers — prostate, the deadly skin disease melanoma and an often fatal childhood tumor called neuroblastoma — also gave positive results in late-stage testing in recent weeks, after decades of struggles in the lab.

many cancer vaccines take a substance from a cancer cell's surface and attach it to something the immune system already recognizes as foreign — in the lymphoma vaccine's case, a shellfish protein.

"It's a mimic to what you're trying to kill, a training device to train the immune system to kill something," Hwu explained.