Inside cells, two important enzymes act like small central regulatory hubs: dipeptidyl peptidase 8 and 9 – DPP8/9 for short. Among other things, they regulate inflammatory reactions and influence whether a survives or dies. These mechanisms are especially important in cancer cells. With the help of drugs that inhibit DPP8/9, tumors can be targeted. However, until now there has been a lack of active compounds that specifically switch off/selectively inhibit only these two enzymes without disrupting other important proteins and processes in the body. Researchers at the Center of Medical Biotechnology (ZMB) at the University of Duisburg-Essen have now made a breakthrough: