A protein that influences the epigenetic characteristics of tumor cells is directly linked to the grade of malignancy of prostate cancer. This key discovery has been made by a team of scientists from the German Cancer Research Center (DKFZ), the University of Zurich, Hamburg-Eppendorf University Hospital, Heidelberg University, and other institutes in a study of 7,700 samples of tumor tissue. The detection of this biomarker may serve as an indicator of the likelihood that the disease may take an aggressive course, and may thus be helpful in choosing an appropriate treatment.