Promising results raise hope for cancer breakthrough: T cells could be tweaked to kill a range of cancers.

In a potential breakthrough in cancer research, scientists at the University of Pennsylvania have genetically engineered patients’ T cells — a type of white blood cell — to attack cancer cells in advanced cases of a common type of leukemia.

Two of the three patients who received doses of the designer T cells in a clinical trial have remained cancer-free for more than a year, the researchers said.