Fig. 1

The description of potential artifacts detected in FFPE samples. a Mutation counts (solid line) and C/T base substitution rates (bar histogram) at two allele frequency ranges across all samples were sorted according to the total mutation counts for given specimen. There was a trend of increasing C/T substitution rate along with total mutation count. Four samples did not follow this trend. Only these samples and none of the others showed very high mutation counts at allele frequencies of more than 10% with the accordingly high C/T substitution rate in this range. Pre-normalization library concentrations were low for all four samples in question. b Per-base Phred quality scores for each position across all samples. Four samples with high mutation counts at allele frequencies of more than 10% are highlighted by bold lines. c Overall sequencing results for all samples. Four samples of interest are respectively highlighted