Harnessing the immune system to fight cancer is revolutionizing treatment, but it has been a tough path to success for certain advanced cancers, such as breast cancer. Now, an engineer from Florida with late-stage breast cancer is the first to celebrate success after a personalized cell treatment, The Guardian reports. Doctors at the National Cancer Institute in Bethesda, Maryland, extracted T cells from the woman’s tumor tissue—called tumor-infiltrating lymphocytes—and then multiplied those primed to attack her particular cancer. They injected 80 billion of these cells back into her body, which wiped out her disease. The woman also received the immune treatment pembrolizumab. Remarkably, she remains cancer-free almost 2 years later, researchers report this week in Nature Medicine. As always, there are caveats: The big one here is that the response of a single patient may not generalize to others. But physicians are hopeful it’s a start.