Serum HER2 as a predictive biomarker for tissue HER2 status and prognosis in patients with gastric cancer

Table 3 Association between clinicopathological variables and serum HER2 extracellular domain concentrations n (%)

Variables	Serum HER2 ECD concentrations		P value
	> 24.75 ng/mL (n = 36)	≤ 24.75 ng/mL (n = 203)
Age (yr)			0.474
≥ 60	17 (47.2)	109 (53.7)
< 60	19 (52.8)	94 (46.3)
Gender			0.396
Male	23 (63.9)	144 (70.9)
Female	13 (36.1)	59 (29.1)
Smoking status			0.452
Never	11 (30.6)	50 (24.6)
Ever	25 (69.4)	153 (75.4)
Tumor location			0.573
GEJ	5 (13.9)	36 (17.7)
Non-GEJ	31 (86.1)	167 (82.3)
Tumor size			< 0.001
≥ 5 cm	27 (75.0)	75 (36.9)
< 5 cm	9 (25.0)	128 (63.1)
Type of gastrectomy			0.266
Total	21 (58.3)	98 (48.3)
Subtotal	15 (41.7)	105 (51.7)
Type of surgery			0.730
Open	25 (69.4)	135 (66.5)
MIS	11 (30.6)	68 (33.5)
Lymph node involvement			0.419
Positive	22 (61.1)	138 (68.0)
Negative	14 (38.9)	65 (32.0)
pTNM stage			0.576
I	6 (16.7)	33 (16.3)
II	12 (33.3)	66 (32.5)
III	13 (36.1)	89 (43.8)
IV	5 (13.9)	15 (7.4)
Lauren classification			0.021
Intestinal type	22 (61.1)	82 (40.4)
Diffuse type	14 (38.9)	121 (59.6)
Tissue HER2 status (IHC/FISH)			< 0.001
Positive	21 (58.3)	18 (8.9)
Negative	15 (41.7)	185 (91.1)

GEJ: Gastroesophageal junction; HER2: Human epidermal growth factor receptor-2; ECD: Extracellular domain; MIS: Minimally invasive surgery; IHC: Immunohistochemistry; FISH: Fluorescence in situ hybridization.