Fig. 2.

Results of EGFR copy number concentration measured by droplet digital PCR (QX200) and digital real-time PCR (LOAA) using 1 ng of genomic DNA isolated from cancer cell lines A549 and NCI-H1975. A and B: Graphs comparing copy numbers of T790M and L858R EGFR mutations and the corresponding wild-type copies in A549 (A) and NCI-H1975 (B). Circles indicate the copy number from the QX200 and crosses indicate the copy number from the LOAA. C: Copy number ratio of each EGFR mutation over wild-type in NCI-H1975 genomic DNA by instrument. Error bars indicate the standard deviation (SD) at each data point with the mean of replicated measurements (n ≥ 5). Significant difference is tested by t-test (p > 0.05, not significant).