Quantitative Analysis of HER2 Amplification by Droplet Digital PCR in the Follow-Up of Gastric Cancer Patients Being Treated with Trastuzumab after Surgery

Table 3

Concordance of plasma and tumor tissue sample results for HER2 status from GC patients by ddPCR or IHC/FISH.

	HER2 in FFPE with ddPCR		Total	Sensitivity	Specificity
	Positive	Negative
HER2 in FFPE with IHC/FISH
Positive	34	5	39	87.2%	95.2%
Negative	3	60	63
HER2 in ctDNA with ddPCR
Positive	26	8	34	76.5%	83.8%
Negative	11	57	68