Table 2.

Characteristics of the studies included in this meta-analysis

Study	Country	Tumor type	Clinical stage	N	Method	Cut-off value	Follow-up	Outcome	Variance analysis	HR
Kimura [15]	Japan	Renal cell carcinoma	I–IV	72	LTIA	8 mg/l	40.6 M (mean)	DSSa	Multivariate	Reported in text
Pierce [16]	USA	Breast cancer	0–III	734	Nephelometry	8.1 mg/l	24 M	OS	Multivariate	Reported in text
Vermaat [17]	Holland	Renal cell cancer	IV	114	ELISA	19.2 ng/ml	27.6 M (mean)	OS	Multivariate	Reported in text
Wood [18]	UK	Renal cell carcinoma	I–IV	119	Nephelometry	NR	2.52 Y (mean)	CSSa	Multivariate	Reported in text
Kwon [19]	South Korea	Gastric cancer	I–IV	115	LTIA	4.2 mg/l	9.3–88.8 M	OS	Multivariate	Reported in text
Wang [20]	China	Esophageal squamous cell carcinoma	I–IV	167	Nephelometry	8 mg/l	NR	OS	Multivariate	Reported in text
Meng [21]	China	Esophageal squamous cell carcinoma	I–IV	252	Nephelometry	8.18 mg/l	65.5 M (median)	OS	Multivariate	Reported in text
Giessen [22]	Germany	Rectal cancer	I–III	256	Nephelometry	5.3 mg/l	8.4 Y (median)	DFS/CSSa	Multivariate	Reported in text
Ni [23]	China	Hepatocellular carcinoma	NR	328	ELISA	7.5 µg/ml	3–32 M	DFS/OS	Multivariate/univariate	Extrapolated from data/reported in text
Haas [24]	Germany	Pancreatic cancer	NR	59	Nephelometry	22.0 mg/l	NR	OS	Univariate	Reported in text
Chen [25]	China	Nasopharyngeal carcinoma	I–IV	419	ELISA	4.28 mg/l	NR	PFS/OS	Univariate	Reported in text
Zhao [26]	China	Non-small cell lung	II–III	114	ELISA	101.4 µg/ml	24.3 M (median)	OS	Multivariate	Reported in text

N number, M month, Y year, NR not reported, DSS disease-specific survival, CSS cancer-specific survival, OS overall survival, DFS disease-free survival, PFS progression-free survival, ELISA enzyme-linked immunosorbent assays, LTIA latex agglutination turbidimetric immunoassay

^aDSS and CSS both are regarded as OS