Assessment of programmed death-ligand 1 expression in primary tumors and paired lymph node metastases of gastric adenocarcinoma

Table 1 Programmed death-ligand 1 expression in primary tumor site and metastatic lymph node

Primary tumor	Total	PD-L1 negative	PD-L1 positive	P value
	n = 68 (%)	n = 44 (%)	n = 24 (%)
Lymph node				< 0.001
PD-L1 negative	51 (75)	40 (90.9)	11 (45.8)
PD-L1 positive	17 (25)	4 (9.1)	13 (54.2)
Total (%)	100.0	64.7	35.3

PD-L1: Programmed death-ligand 1.

Table 2 Clinical characteristics according to the positivity for programmed death-ligand 1 in the primary tumor and lymph node metastasis

Variables	Primary tumor		P value	Lymph node		P value
	PD-L1(-), n = 44 (%)	PD-L1+, n = 24 (%)		PD-L1(-), n = 51 (%)	PD-L1+, n = 17 (%)
Sex			0.417			0.558
Female	14 (31.8)	10 (41.7)		19 (37.3)	5 (29.4)
Male	30 (68.2)	14 (59.3)		32 (62.7)	12 (70.6)
Age (yr)			0.721			0.127
mean (SD)	60.7 (11.8)	61.7 (12.3)		59.8 (12.4)	64.9 (9.7)
BMI (kg/cm²)			0.717			0.271
mean (SD)	24.3 (5.6)	23.9 (3.9)		24.6 (5.2)	23.0 (4.5)
Hemoglobin (g/dL)			0.008a			0.148
mean (SD)	12.4 (2.1)	10.8 (2.5)		12.1 (2.2)	11.1 (2.7)
Neutrophil-lymphocyte ratio			0.703			0.879
mean (SD)	3.30 (4.43)	3.72 (4.21)		3.39 (4.69)	3.31 (3.08)
CCI			0.974			0.539
CCI 0	31 (70.5)	17 (70.8)		35 (68.6)	13 (76.5)
CCI ≥ 1	13 (29.5)	7 (29.2)		16 (31.4)	4 (23.5)
Tumor site			0.635			0.317
Lower	25 (56.8)	15 (62.5)		32 (62.7)	8 (47.1)
Middle	12 (27.3)	6 (25)		11 (21.6)	7 (41.2)
Upper	4 (9.1)	3 (12.5)		5 (9.8)	2 (11.8)
All	3 (6.8)	0 (0)		3 (5.9)	0 (0)
Type of resection			0.323			0.122
Subtotal	22 (50)	9 (37.5)		26 (51)	5 (29.4)
Total	22 (50)	15 (62.5)		25 (49)	12 (70.6)

^aP < 0.05.

PD-L1: Programmed death-ligand 1; BMI: Body mass index; CCI: Charlson-Deyo Comorbidity Index.

Table 3 Pathological characteristics according to the positivity for programmed death-ligand 1 in the primary tumor and lymph node metastasis

Variables	Primary tumor		P value	Lymph node		P value
	PD-L1(-), n = 44 (%)	PD-L1+, n = 24 (%)		PD-L1(-), n = 51 (%)	PD-L1+, n = 17 (%)
Tumor size (cm)			0.011			0.005
mean (SD)	5.8 (3.3)	8.1 (3.6)		5.9 (3.3)	8.7 (3.5)
Lauren type			0.952			1
Intestinal	18 (40.9)	10 (41.7)		21 (41.2)	7 (41.2)
Diffuse/mixed	26 (59.1)	14 (58.3)		30 (58.8)	10 (58.8)
Grade of histological differentiation			0.438			0.449
Well/mod differentiated	15 (34.1)	6 (25)		17 (33.3)	4 (23.5)
Poorly differentiated	29 (65.9)	18 (75)		34 (66.7)	13 (76.5)
Lymphatic invasion			0.176			1
No	14 (31.8)	4 (16.7)		14 (27.5)	4 (23.5)
Yes	30 (68.2)	20 (83.3)		37 (72.5)	13 (76.5)
Venous invasion			0.017			0.262
No	28 (63.6)	8 (33.3)		29 (56.9)	7 (41.2)
Yes	16 (36.4)	16 (66.7)		22 (43.1)	10 (58.8)
Perineural invasion			0.417			0.558
No	14 (31.8)	10 (41.7)		19 (37.3)	5 (29.4)
Yes	30 (68.2)	14 (58.3)		32 (62.7)	12 (70.6)
Peritumoral inflammatory response			< 0.001			0.011
Absent/mild	32 (72.7)	6 (25)		33 (64.7)	5 (29.4)
Moderate/severe	12 (27.3)	18 (75)		18 (35.3)	12 (70.6)
pT status			0.734			0.268
pT1/T2	8 (18.2)	3 (12.5)		10 (19.6)	1 (5.9)
pT3/T4	36 (81.8)	21 (87.5)		41 (80.4)	16 (94.1)
No. of lymph nodes			0.964			0.035
mean (SD)	42.3 (13.9)	42.5 (19.4)		40.1 (14.3)	49.4 (18.7)
No. of positive lymph nodes			0.961			0.486
mean (SD)	7 (6.4)	6.9 (6.9)		6.7 (6.1)	7.9 (7.7)
pN status			1			0.879
pN1	9 (20.5)	5 (20.8)		11 (21.6)	3 (17.6)
pN2	18 (43.2)	11 (45.8)		23 (45.1)	7 (41.2)
pN3	16 (36.4)	8 (33.3)		17 (33.3)	7 (41.2)
pTNM status			1			0.299
I/II	9 (20.5)	5 (20.8)		12 (23.5)	2 (11.8)
III/IV	35 (79.5)	19 (79.2)		39 (76.5)	15 (88.2)

P values in bold are statistically significant. PD-L1: Programmed death-ligand 1.