Table 4. Univariate and multivariate Cox regression analysis of overall survival.

	Univariate analysis			Multivariate analysis
	HR	95% CI	P value	HR	95% CI	P value
Low MLH1	1
High MLH1	0.798	0.433–1.470	0.470
Low MSH2	1
High MSH2	0.786	0406–1.523	0.476
Low PD-1	1
High PD-1	0.441	0.242–0.804	0.008	0.507	0.273–0.941	0.031
Low PD-1L	1
High PD-1L	1.204	0.640–2.264	0.565
Moderate Stroma	1
Dense Stroma	0.972	0.541–1.747	0.925
Age (< 60 years)	1
Age (≥ 60 years)	0.765	0.415–1.409	0.390
Gender (Male)	1
Gender (Female)	0.896	0.482–1.666	0.728
Tumor site (Head, neck)	1
Tumor site (Body, tail)	1.486	0.824–2.680	0.188
T stage (T1+T2)	1
T stage (T3+T4)	1.992	0.889–4.467	0.094
N stage (N0)	1
N stage (N1)	1.212	0.670–2.191	0.525
Metastasis (M0)	1
Metastasis (M1)	0.584	0.141–2.413	0.457
Differentiation (G1, G2)	1
Differentiation (G3)	1.963	1.084–3.553	0.026	2.504	1.307–4.798	0.006
Vascular invasion (No)	1
Vascular invasion (Yes)	4.027	1.940–8.360	< 0.001	5.931	2.657–13.238	< 0.001
Nervous invasion (No)	1
Nervous invasion (Yes)	1.917	0.969–3.793	0.062

HR: hazard ratio, 95% CI: 95% confidence interval.

Significant values (P < 0.05) have been marked with bold.