![Researchers Lelisa F. Gemta (left) and Timothy Bullock have determined why killer T cells can be so helpless against cancer. Their discovery could help doctors make the immune cells much more effective against cancer.](https://makingofmedicine.virginia.edu/wp-content/uploads/2019/02/Tim_Bullock_-_Lelisa_Gemta_WEB-351x244.jpg)
Our Timothy Bullock, PhD, and his team have discovered a defect in immune cells known as “killer T cells” that explains why they struggle to destroy cancer tumors. By fixing this defect, scientists could make the cells much better at killing cancer cells.