Relationship between Helicobacter pylori infection and programmed death-ligand 1 in gastric cancer: A meta-analysis

Table 1 Characteristics of the included studies, n (%)

Ref.	Design	Country	Diagnosis	Sample size	Mean age (years)	Men (%)	Stage	HP evaluation	HP positive	PD-L1 evaluation and cutoffs	PD-L1 expression
Koizumi et al[27], 2022	CS	Japan	Patients with GC after resection who underwent R0 gastrectomy	491	69	67.0	I-III	Immunohistochemistry	175 (35.6)	IHC (≥ 10%)	152 (30.9)
Shen et al[28], 2019	CS	China	Patients with early GC	54	65	46.3	I	Pathological evaluation or histological immunostaining	19 (35.2)	IHC (≥ 1%)	24 (44.4)
Yoshida et al[29], 2022	CS	Japan	Patients with GC or GEJC for total or partial	106	68	67	I-IV	Biopsy, serum test, or breath antibody test	53 (50.0)	CPS (≥ 1)	73 (68.9)
Böger et al[30], 2016	CS	Germany	Patients with GC or GEJC for total or partial gastrectomy	392	68	62.4	I-IV	Histological PCR	61 (15.9)	IHC (≥ 5%)	93 (23.7)
Che et al[18], 2022	CS	China	Patients with GC or GEJC	25	NA	70.1	III-IV	Histopathology, HpSA, or breath antibody test	14 (56.0)	NA	8 (32.0)
Magahis et al[31], 2023	CS	United States	Patients with stage IV GC	121	59	65.1	IV	Histopathology, serum test, or breath antibody test	25 (20.7)	CPS (≥ 1%)	76 (62.8)
Wu et al[32], 2017	CS	China	Patients with GC for total or partial gastrectomy	102	NA	74.7	I-IV	Serum test	62 (60.8)	IHC (≥ 5%)	62 (60.8)
Jia et al[17], 2024	CS	China	Patients with GC	562	NA	48.9	I-IV	Breath antibody test	290 (51.6)	CPS (≥ 1%)	331 (58.9)
Liu et al[33], 2020	CS	Korea	Patients with GC for gastrectomy	127	64	66.0	I-IV	Pathological evaluation or histological	55 (43.3)	CPS (≥ 1%)	74 (58.3)
Di Bartolomeo et al[34], 2015	CS	Italy	Patients with GC after resection	55	62	64	II-III	Pathological evaluation or histological immunostaining	23 (41.8)	IHC (≥ 5%)	37 (67.3)
Kuo et al[35], 2017	CS	Korea	Patients with GC after radical resection	112	NA	NA	I-IV	Histological PCR	43 (38.4)	IHC (≥ 5%)	35 (31.3)
Sughayer et al[36], 2020	CS	Jordan	Patients with GC for total or partial gastrectomy	92	63	61	I-IV	Pathological evaluation or histological immunostaining	10 (10.9)	CPS (≥ 1%)	63 (68.5)
Tseng et al[37], 2020	CS	China	Patients with GC after radical resection	370	NA	81	I-III	Histological PCR	97 (26.2)	CPS (≥ 1%)	78 (21.4)
Fang et al[38], 2020	CS	China	Patients with GC after radical resection	460	NA	71	I-III	Histological PCR	157 (34)	CPS (≥ 1%)	140 (30.0)

HP: Helicobacter pylori; PD-L1: Programmed death ligand-1; CS: Cross - sectional study; GC: Gastric cancer; IHC: Immunohistochemistry; GEJC: Gastroesophageal junction cancer; CPS: Combined positive score; PCR: Polymerase chain reaction; NA: Not available; HpSA: Helicobacter pylori stool antigen.