The powerful master regulatory transcription factor called Bcl6 is key to the survival of a majority of aggressive lymphomas, which arise from the B-cells of the immune system. The protein has long been considered too complex to target with a drug since it is also crucial to the healthy functioning of many immune cells in the body, not just B cells gone bad. But now, in the journal Nature Immunology, researchers at Weill Cornell Medical College report that it is possible to shut down Bcl6 in the cancer, known as diffuse large B-cell lymphoma (DLBCL), while not affecting its vital function in T cells and macrophages that are needed to support a healthy immune system.