Table 2.

Summary of mutations identified in serial tumor samples (S1, S2, and S3) using MALDI-TOF mass spectrometry and Illumina TruSeq sequencing and their allele frequencies

Mutations identified	Methods		Allele frequency (%)			Target coverage at variant site			Mean target coverage
	MALDI-TOF	TruSeq	S1	S2	S3	S1	S2	S3	S1	S2	S3
APC c.4285delC (p.Gln1429fs)	Not tested by panel	Detected	52	NA	85	7378×	NA	6420×	5115×	NA	4332×
BRAF c.1742A>G (p.Asn581Ser)	Not tested by panel	Detected	30	NA	42	8771×	NA	9260×	5115×	NA	4332×
ERBB2c.2264T>C (p.Leu755Ser)	Detected	Detected	33	57	68	8171×	NA	7056×	5115×	NA	4332×

S1, S2, and S3 represent sample 1 (primary rectal tumor collected in 2008), sample 2 (tumor from 2011 liver resection), and sample 3 (tumor from 2013 liver biopsy), respectively. S1 and S3 were profiled using Illumina TruSeq sequencing and S2 was profiled using MALDI-TOF mass spectrometry.

MALDI-TOF, matrix-assisted laser desorption/ionization time of flight; NA, not applicable.