Vinay Kumar, MBBS, MD, FRCPath, Professor and Chairman, Department of Pathology, University of Chicago, Pritzker School of Medicine, Chicago, U.S, Abul K. Abbas, MBBS, Distinguished Professor and Chair, Department of Pathology, University of California San Francisco, San Francisco, California and Nelson Fausto, MD, Professor and Chair, Department of Pathology, University of Washington, Seattle, Washington