Table 2.

Univariate and multivariate analysis results of clinicopathological characteristics and preoperative sPD-L1 as well as exoPD-L1

Variables	Relapse-free survival				Overall survival
	Univariate analysis		Multivariate analysis		Univariate analysis		Multivariate analysis
	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Age (> 65 vs. ≤ 65)	0.905(0.561 − 1.460)	0.682			1.582(0.857 − 2.918)	0.142
Gender (Female vs. male)	1.009(0.673 − 1.514)	0.966			0.918(0.524 − 1.606)	0.763
Primary tumor site (Right-sided vs. Left-sided)	0.919(0.574 − 1.473)	0.727			0.925(0.463 − 1.844)	0.824
Tumor grade (G3 vs. G1–2)	1.805(1.180 − 2.762)	0.007	1.909(1.208 − 3.018)	0.006	1.474(0.810 − 2.681)	0.204
Pathological type (Mucinous vs. Non-mucinous)	3.094(0.965 − 9.925)	0.058			0.53(0.073 − 3.856)	0.531
T-stage (T4 vs. Tis-3)	1.101(0.720 − 1.684)	0.657			1.853(1.044 − 3.291)	0.035	1.747(1.040 − 2.936)	0.035
N-stage (N1–2 vs. N0)	1.898(1.227 − 2.936)	0.004	1.668(1.069 − 2.604)	0.024	2.291(1.211 − 4.335)	0.011
Preoperative CEA (> 200 vs. ≤ 200 ng/ml)	1.584(0.694 − 3.616)	0.275			3.087(1.316 − 7.243)	0.010
Interval from primary tumor resection to liver metastases (≤ 12 vs. > 12 months)	1.208(0.742 − 1.968)	0.448			1.689(0.902 − 3.163)	0.102
Number of metastases (> 1 vs. ≤ 1)	1.954(1.305 − 2.924)	0.001			1.262(0.730 − 2.183)	0.405
Size of the largest metastasis (> 5 cm vs. ≤ 5 cm)	2.359(1.395 − 3.989)	0.001	2.314(1.310 − 4.089)	0.004	4.54(2.402 − 8.583)	< 0.001	3.622(1.719 − 7.631)	0.001
Preoperative chemotherapy (Yes vs. no)	2.146(1.435 − 3.208)	< 0.001	2.449(1.596 − 3.758)	< 0.001	1.400(0.804 − 2.438)	0.234
Postoperative chemotherapy (Yes vs. no)	0.846(0.551 − 1.298)	0.444			0.449(0.257 − 0.784)	0.005
Ablation (Yes vs. no)	1.723(1.003 − 2.961)	0.049			1.461(0.617 − 3.46)	0.388
Exosomal PD-L1 (High vs. low)	1.747(1.184 − 2.576)	0.005	1.555(1.033 − 2.342)	0.035	2.197(1.280 − 3.772)	0.004	2.120(1.160 − 3.874)	0.015
Soluble PD-L1 (High vs. low)	1.823(1.242 − 2.676)	0.002			2.133(1.225 − 3.714)	0.007