RET and thyroid cancer: As opposed to adult thyroid cancer, we identified few BRAF/RAS pathogenic variants and many gene fusions in malignant pediatric nodules: 11 (22%) malignant nodules harbored BRAF/RAS pathogenic variants while 29 (58%) harbored a gene fusion. Fusions largely (26 of 29 [90%]) involved RET and NTRK1/3 but were also found in ALK, BRAF, and PPARG (eFigure 2 in the Supplement).