Table 2. Comparison of allele frequencies of EGFR mutations in cfDNA samples of NSCLC patients as determined by digital PCR and targeted sequencing.

Case No	EGFR mutation	Allele frequency in pre-RT by digital PCR (copy/mL)	Allele frequency during RT by digital PCR (copy/mL)	Allele frequency in pre-RT by targeted sequencing	Allele frequency during RT by targeted sequencing
case 1	-	-	-	N.D.	7.8% (G719C)
case 2	L858R	N.D (0)	0.9% (10562)	N.D.	0.5%
case 12	exon 19 del.	0.2% (20866)	0.4% (139579)	N.D.	N.D.
case 15	L858R	44194 (0·5%)	2.3%(363269)	0.3%	1.5%
	T790M	N.D. (0)	0.4% (40824)	N.D.	0.3%
case 16	L858R	(N.D.)	0·2%	N.D.	2.8%
	L747S	-	-	N.D.	2.3%
case 17	exon 19 del.	N.D. (64282)	6.4% (2122718)	0.3%	7.3%

Note: del., deletion; N.D., not determined; RT, radiotherapy.