NRAS and cancer: We compared the ERK score, a measure of ERK activity derived from RNAseq data, from RET-rearranged, BRAF mutant, and RAS mutant papillary thyroid cancers in TCGA patients, and we found that RET-rearranged cancers have significantly higher ERK scores than either BRAF or NRAS/HRAS mutant tumors (Fig. S2).