q61r mutation in multiple tumor samplings over space and time and circulating tumor DNA. Detection of the NRAS Q61R mutation in tumor samples from the original SBT (Sample 9P1-9P3, top panels) and first LGSC recurrence (Sample 9R1-9R3, middle panels) by the Raindance Raindrop digital PCR assay are shown. Mutation status was also determined in the ctDNA sample obtained following the second LGSC recurrence (Sample 9CTDNA), corresponding normal (Sample 9 N) and non template control (NTC) (bottom panels). The wild type ('WT’) and mutant ('MUT’) population are circled in each panel, with the % MUT indicated in the top right corner (MUT drops/total of WT + MUT droplets). Consistent with Ion Torrent and MiSeq, the NRAS Q61R mutation was observed in all 6 tumor samples and the ctDNA sample, and was not detected in the corresponding normal.