Formalin fixation on HER-2 and PD-L1 expression in gastric cancer: A pilot analysis using the same surgical specimens with different fixation times

Table 3 Human epidermal growth factor receptor 2 immunohistochemistry and dual color in situ hybridization results in Human epidermal growth factor receptor 2-immunoreactive cases (n = 8)

Case No.	Formalin	HER-2 IHC score; P = 1.000 (6 h-48 h vs 1 wk)1				DISH; HER2/CEP17ratio (average HER2 copy number); P = 0.6989 (6 h-48 h vs 1 wk)1				Final assessment
		6 h	24 h	48 h	1 wk	6 h	24 h	48 h	1 wk
12	10% F	3+	3+	3+	3+	11.4 (33.7)	10.9 (28.5)	7.1 (20.4)	4.8 (17.4)	+
14	10% F	1+	2+	0	0	1.2 (3.0)	1.3 (3.3)	1.3 (2.2)	1.3 (2.2)	-
20	10% F	2+	0	0	0	0.8 (2.1)	1.2 (2.8)	1.3 (2.1)	1.3 (2.0)	-
22	10% F	1+	1+	2+	2+	1.6 (3.4)	1.9 (4.4)	2.1 (2.5)	2.1(2.8)	+
25	10% NBF	0	1+	2+	1+	1.0 (1.9)	1.1 (2.2)	1.8 (3.1)	1.4 (2.5)	-
26	10% NBF	2+	2+	2+	2+	2.6 (5.2)	3.7 (6.5)	3.5 (6.6)	3.3 (5.7)	+
27	10% NBF	2+	1+	1+	3+	1.1 (2.9)	1.4 (2.8)	1.3 (2.1)	2.2 (4.9)	+
31	10% NBF	3+	3+	3+	3+	4.7 (19.8)	6.7 (21.2)	4.7 (15.7)	7.2 (21.2)	+

¹Simultaneous tests for linear hypotheses based on a linear mixed effects model.

F: Formalin; NBF: Neutral buffered formalin; DISH: Dual color in situ hybridization; HER-2: Human epidermal growth factor receptor 2; PD-L1: Programmed death-ligand 1.