Table 1. Association of MT staining and clinicopatological factors. Tumor type not taken into account.

Factor	Number of studies	Number of participants	OR/HR* (95% CI)	Heterogeneity		Publication bias	Model
				P-value	I2 (%)	P-value
Age	9	1069	1.07 (0.82–1.39)	0.679	0.00	0.117	Fixed effects
Gender	9	944	0.99 (0.74–1.34)	0.393	5.08	0.611	Fixed effects
Tumor vs. control	31	2454	1.19 (0.47–3.01)	0.000	89.58	0.236	Random effects
Tumor stage	19	1237	1.15 (0.74–1.77)	0.000	60.83	0.987	Random effects
Tumor size	6	1962	1.37 (0.45–4.13)	0.000	90.88	0.194	Random effects
Tumor grade	33	2504	1.58 (1.08–2.30)	0.000	66.57	0.886	Random effects
Metastases, nodal + distant	21	1987	1.59 (1.03–2.46)	0.000	71.68	0.039	Random effects
Metastases, distant	6	741	1.56 (0.56–4.37)	0.014	64.82	0.075	Random effects
Metastases, nodal	15	1246	1.62 (0.98–2.68)	0.000	72.92	0.201	Random effects
Overall survival	10	2041	2.04 (1.47–2.81)	0.000	97.69	0.572	Random effects

Heterogeneity of studies analyzed using Cochran's Q-test (p-value displayed) and using I². Egger's two-tailed test used for publication bias analysis (p-value displayed). * effect measure is odds ratio, OR, except for survival analysis using hazard ratio, HR. CI, confidence interval