Figure 1.

Examples of mismatch ratios of other normal samples for mutation candidates with moderate P-values. In both cases, although the mismatch ratios of the target tumour sample were relatively high, the numbers of corresponding supporting variant reads were small. For the candidate on the left, the frequencies of non-reference alleles for other normal samples were consistently zero. Therefore, this supports the prediction that the observed variant reads in the target tumour sample came from a true somatic mutation and not from sequencing errors. On the other hand, for the candidate on the right, we often observed high frequencies of non-reference alleles for several different normal samples. Therefore, the observed variant reads in the target tumour sample likely came from sequencing errors, and it was just by chance that there was no variant read in the target normal sample.