Table 3.

Analysis of EGFR Mutations in Circulating Tumor Cells and Free Plasma DNA and the Concordance with Tumor Mutation.^*

Patient No., EGFR Mutation Status, and Response to Therapy	SARMS Assay Results†						Concordance with Tumor Mutation‡
	Circulating Tumor Cells			Free Plasma
	primary mutation	T790M	other	primary mutation	T790M	other
EGFR mutation present and response during therapy§
1	Del	No		UN	UN		C¶||
9	Del	Yes		None detected	Yes		C
11	Del	No		None detected	No		C
21	Del	No		Del	Yes		NA
22	Del	No	G719X	None detected	Yes		C
23	Del	Yes	L858R	Del	Yes	L858R	C,P
EGFR mutation present and disease progression during therapy§
3	Del	No	G719X	UN	UN		C¶
6	Del	Yes		Del	No		C,P
7	None detected	Yes		L858R	Yes		P
10	L858R	Yes	Del	None detected	No		C
12	Del	Yes		None detected	No		C
13	Del	Yes		Del	Yes		C,P
14	Del	No		None detected	No		C
15	Del	No		None detected	No		C
16	Del	Yes		None detected	No		C
17	Del	Yes		Del	Yes		NA
18	Del	No	G719X	None detected	No		NA
20	Del	No		None detected	No		NA**
45	Del	Yes		None detected	No		NA
46	Del	Yes		Del	Yes		NA
EGFR mutation absent
26	None detected	No		None detected	No		C,P
43	None detected	No		None detected	No		C,P
44	None detected	No		None detected	No		C,P

^*Listed are patients in Group A, for whom genotypes were available from at least two of the following: circulating tumor cells, plasma, and tumor-biopsy specimens. Molecular analyses of circulating tumor cells and plasma were performed within 6 months after the initial quantitation of circulating tumor cells. Del denotes deletions in exon 19, NA not applicable due to unavailable tumor specimen, SARMS Scorpion Amplification Refractory Mutation System, and UN sample unavailable for analysis.

^†The primary activating EGFR mutations are listed when present, including the presence or absence of the specific drug-resistance allele T790M. In all cases, other activating mutations that are listed as “other” were present at a lower allele frequency than that of the primary mutation.

^‡Listed is the concordance between the presence of the primary mutation in the tumor specimen and that in circulating tumor cells (C) and free plasma DNA (P).

^§Patients who were receiving EGFR tyrosine kinase inhibitors were classified as having either a response or disease progression at the time of the analysis of circulating tumor cells.

^¶A plasma specimen was not available for this patient.

^||The mutation in the primary tumor was detected by high-performance liquid chromatography but was below the level of detection by standard sequencing analysis.

^**The presence of a mutation of unknown significance (S885L) that was not included in the SARMS assay was reported in the primary tumor. An additional tumor specimen was not available for SARMS analysis.