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

Table 2

Dynamics of plasma HER2 ratios in GC patients by ddPCR during the follow-up period.

Patient ID	HER2 ratios							Best response	PFS (months)
	0 months	2 months	4 months	6 months	8 months	10 months	12 months
1	4.59	2.44	2.23	0.89	0.71	1.58	1.04	PR	12
2	2.84	1.55	1.34	2.74	3.56	—	—	SD	6
3	5.95	2.14	1.74	2.29	1.84	3.46	3.28	PR	10
4	6.25	1.61	1.12	1.52	1.05	0.78	1.28	PR	12
5	8.19	2.91	1.54	1.06	2.12	4.88	4.64	PR	10
6	5.34	1.18	2.06	3.13	4.02	6.14	—	PR	8
7	4.79	2.53	1.02	1.54	2.4	3.64	3.88	PR	10
8	5.17	1.52	1.44	0.73	1.03	1.13	0.86	PR	12
9	2.72	1.31	2.29	3.54	4.22	—	—	SD	6
10	3.17	1.24	0.89	1.06	1.45	1.06	1.11	PR	12
11	4.44	1.88	1.59	2.04	3.15	5.28	—	PR	8
12	3.48	1.42	1.89	1.04	0.94	1.22	1.08	SD	12

SD: stable disease; PR: partial response; PFS: progress free survival; means time to progressive disease.