Scientists may have found a way around the limitations of engineered T cells by borrowing a few tricks from cancer itself. By studying mutations in malignant T cells that cause lymphoma, they zeroed in on one that imparted exceptional potency to engineered T cells. Inserting a gene encoding this unique mutation into normal human T cells made them more than 100 times more potent at killing cancer cells without any signs of becoming toxic. While current immunotherapies work only against cancers of the blood and bone marrow, the engineered T cells were able to kill tumors derived from skin, lung and stomach in mice. The team has already begun working toward testing this new approach in people.