Table 2. Univariate and multivariate Cox regression analyses of potential prognostic factors for overall survival.

	Overall survival
	Training set		Validation set
Variable	HR (95% CI)	P	HR (95% CI)	P
Univariate
Tumour size	1.22 (1.12–1.34)	<0.001	1.33 (1.22–1.46)	<0.001
T stage		0.001		<0.001
2 vs 1	3.61 (1.56–8.35)	0.003	5.46 (2.01–14.84)	0.001
3 vs 1	3.71 (1.81–7.62)	<0.001	4.85 (2.22–10.57)	<0.001
N status (N1 vs N0)	4.48 (1.06–18.93)	0.042	31.90 (6.87–148.18)	<0.001
M status (M1 vs M0)	21.21 (4.09–109.93)	<0.001	9.59 (3.18–28.93)	<0.001
TNM stage		<0.001		<0.001
II vs I	3.39 (1.65–6.96)	0.001	2.84 (1.21–6.64)	0.016
III vs I	17.69 (6.46–48.43)	<0.001	30.95 (9.42–101.69)	<0.001
IV vs I	59.07 (10.34–337.40)	<0.001	59.85 (12.65–283.10)	<0.001
Fuhrman grade		<0.001		<0.001
2 vs 1	0.65 (0.20–2.12)	0.470	1.01 (0.19–5.22)	0.994
3 vs 1	2.74 (1.00–7.50)	0.049	7.18 (1.66–9.31.15)	0.008
4 vs 1	8.43 (2.96–24.01)	<0.001	16.09 (3.39–76.43)	0.005
Tumour necrosis
Present vs absent	1.97 (1.04–3.71)	0.037	6.22 (2.82–13.74)	<0.001
ECOG-PS (⩾1 vs 0)	2.21 (1.16–4.22)	0.016	4.40 (2.09–9.25)	<0.001
CXCR4 (high vs low)	4.32 (1.98–9.42)	<0.001	3.57 (1.69–7.56)	0.001
Multivariate
Tumour size	1.03 (0.92–1.16)	0.588	1.06 (0.92–1.21)	0.409
TNM stage
III+IV vs I+II	4.96 (1.78–13.84)	0.002	9.06 (2.89–28.37)	<0.001
Fuhrman grade
3+4 vs 1+2	4.16 (1.95–8.87)	<0.001	4.53 (1.71–12.00)	0.002
Tumour necrosis
Present vs absent	1.27 (0.57–2.84)	0.504	1.90 (0.71–5.08)	0.325
ECOG-PS (⩾1 vs 0)	2.11 (1.01–4.40)	0.047	2.76 (1.22–6.26)	0.015
CXCR4 (high vs low)	3.38 (1.49–7.68)	0.004	2.88 (1.26–6.59)	0.012

Abbreviations: CI=confidence interval; CXCR4=CXC chemokine receptor 4; ECOG-PS=Eastern Cooperative Oncology Group performance status; HR=hazard ratio.