The metabolic enzyme IL4I1 (interleukin-4-induced-1) promotes the spread of tumor cells and suppresses the immune system. This was discovered by scientists from the Berlin Institute of Health (BIH) together with colleagues from the German Cancer Research Center (DKFZ) in Heidelberg. The enzyme is produced to a greater extent in tumors and activates the dioxin receptor. Compounds that inhibit IL4I1 could open up new opportunities for cancer therapy in the future. The results of this study have now been published in the journal Cell.