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. 2021 May 2;112(6):2371–2380. doi: 10.1111/cas.14879

FIGURE 2.

FIGURE 2

Detection of epidermal growth factor receptor (EGFR) T790M and C797S by droplet digital PCR (ddPCR). Detection of T790M and C797S in the trans position was possible using ddPCR. A, Detection of EGFR T790M and C797S with Sanger sequencing from JFCR163. B, Detection of EGFR C797S mutation with ddPCR from JFCR 163. Mutant positive template is depicted with blue dots. C, Example of our original ddPCR probe to distinguish cis or trans EGFR‐T790M and C797S mutations. T790M mutation was detected as FAM positive with low amplitude and depicted with blue dots. C797S and T790M in cis position was detected as FAM positive with high amplitude and depicted with blue dots. C797S in trans position was detected as both FAM and HEX positive and depicted with yellow dots. D, Sample from patient No. 4 (JFCR‐129‐2) showed yellow dots positive with ddPCR, which indicated the detection of T790M and C797S in the trans position. E, T790M and C797S in the trans position was also confirmed by NGS using the PCR amplified exon 20 of EGFR, the results of JFCR‐129‐2. (JFCR‐129‐1 as a comparison)