Pier Giuseppe Pelicci is Director of Research and Chairman of the Department of Experimental Oncology of the European Institute of Oncology (IEO), in Milan. He is also full professor at the University of Milan, President of the European School of Molecular Medicine (SEMM), and Scientific Director of Alleanza Contro il Cancro (ACC), a network of 25 cancer research hospitals promoted and coordinated by the Ministry of Health, engaged in the set-up of multicentric mechanism–based clinical trials. With a medical degree, a specialty in Internal Medicine and a PhD in Molecular Biology, he devoted his life to research, contributing to seminal discoveries in the elucidation of mechanisms of tumorigenesis (such as the identification /functional characterization of PML-RAR and mutated NPM oncogenes in myeloid leukemia) and the definition of the molecular bases of some of currently used targeted treatments (such as retinoic acid, HDAC- or histone- demethylase inhibitors). More recently, he has been focusing on the biological and molecular characterization of normal and cancer stem cells, in leukemia and breast cancer, and mechanisms of DNA damage accumulation in normal and cancer cells.