Table 2. Correlation between VETC presenting and PD-L1 expression with clinicopathologic characteristics of the whole ICC series (n=412).

Characteristics	Training cohort (n=214)								Validation cohort (n=108)								External validation cohort (n=90)
	VETC				PD-L1				VETC				PD-L1				VETC				PD-L1
	Absent	Present	P		Low	High	P		Absent	Present	P		Low	High	P		Absent	Present	P		Low	High	P
Gender
Male	56	67	0.231		55	68	0.072		27	44	0.767		32	39	0.155		16	37	0.962		25	28	0.533
Female	34	57			52	39			13	24			22	15			11	26			15	22
Age, year
≤58	54	63	0.182		65	52	0.074		19	33	0.917		22	30	0.123		16	38	0.925		25	29	0.665
>58	36	61			42	55			21	35			32	24			11	25			15	21
HBsAg
Negative	50	81	0.147		73	58	0.035		18	20	0.101		32	6	<0.001		8	12	0.268		14	6	0.009
Positive	40	43			34	49			22	48			22	48			19	51			26	44
AFP (ng/mL)
≤20	79	114	0.313		97	96	0.818		33	60	0.405		48	45	0.403		22	58	0.143		35	45	0.746
>20	11	10			10	11			7	8			6	9			5	5			5	5
CA-199 (U/mL)
<37	35	68	0.021		49	54	0.494		16	44	0.012		32	28	0.438		8	34	0.007		24	23	0.186
≥37	55	56			58	53			24	24			22	26			18	29			16	27
Liver cirrhosis
Absent	68	93	0.925		88	73	0.017		28	54	0.269		36	46	0.024		21	41	0.233		28	34	0.838
Present	22	31			19	34			12	14			18	8			6	22			12	16
Tumor size (cm)
≤5	35	56	0.359		43	48	0.489		16	38	0.111		26	28	0.700		10	23	0.961		26	7	<0.001
>5	55	68			64	59			24	30			28	26			17	40			14	43
Tumor number
Single	71	97	0.907		86	82	0.505		26	50	0.348		41	35	0.206		22	47	0.591		32	37	0.387
Multiple	19	27			21	25			14	18			13	19			5	16			18	13
Microvascular invasion
Negative	70	111	0.018		92	89	0.570		30	65	0.003		48	47	0.767		18	57	0.005		36	39	0.161
Positive	20	13			15	18			10	3			6	7			9	6			4	11
Tumor encapsulation
None	84	109	0.187		98	95	0.491		33	57	0.858		44	46	0.605		23	48	0.409		32	39	0.817
Complete	6	15			9	12			7	11			10	8			4	15			8	11
Tumor differentiation
I+II	57	78	0.948		67	68	0.887		23	41	0.775		35	29	0.240		22	59	0.121		35	46	0.503
III+IV	33	46			40	39			17	27			19	25			5	4			5	4
Lymphonodus metastasis
Absent	82	98	0.017		96	84	0.024		29	60	0.038		48	41	0.076		24	42	0.037		20	42	0.0005
Present	8	26			11	23			11	8			6	3			3	21			20	8
TNM stage
I	73	93	0.290		84	82	0.743		29	54	0.411		43	40	0.493		21	46	0.842		31	35	0.424
II+III	17	31			23	25			11	14			11	14			7	17			9	15
Child-Pugh stage
0-A	86	119	0.882		105	100	0.088		39	67	>0.99		54	52	0.495		18	47	0.258		20	45	0.010
B-C	4	5			2	7			1	1			0	2			10	15			20	15
Follow-up
Early recurrence (≤2 years)	38	65	0.014		52	51	0.667		39	24	0.037		31	32	0.996		9	29	0.009		10	28	0.091
Late recurrence (>2 years)	17	10			12	15			2	6			4	4			6	2			5	3

*, P value <0.05 showed statistical significant. CA-199, carbohydrate antigen 199; TNM, tumor-nodes-metastases; VETC, vessels encapsulate tumor clusters; ICC, intrahepatic cholangiocarcinoma.