1. From the Princess Máxima Center for Pediatric Oncology (I.M.S., P.E.S.-H., R.P.), and the Dutch Childhood Oncology Group (I.M.S., R.P.) — both in Utrecht, the Netherlands; Tettamanti Center (P.L.) and Biostatistics and Clinical Epidemiology (M.G.V.), Fondazione IRCCS San Gerardo dei Tintori, Monza, the School of Medicine and Surgery, University of Milano-Bicocca, Milan (M.G.V.), and the Department of Pediatric Hematology–Oncology and Cell and Gene Therapy, IRCCS Ospedale Pediatrico Bambino Gesù, Catholic...