Background: High expression of programmed death ligand-1 (PD-L1) has been related to good response to immunotherapy patients with gastric cancer (GC). However, the influence of Helicobacter pylori (HP) infection on PD-L1 expression in GC remains unknown. A meta-analysis was performed to evaluate the association between HP infection and PD-L1 expression in GC.
Methods: Observational studies that investigated the relationship between HP infection and PD-L1 expression in patients with GC were obtained by search electronic databases, including PubMed, Embase, Cochrane's Library and Web of Science. A random-effect model incorporating the possible influence of between-study heterogeneity was used to pool the results.
Results: Ten studies with 1870 patients with GC contributed to the meta-analysis. Pooled results showed that HP infection was significantly associated with the tumour expression of PD-L1 (odds ratio [OR]: 1.90, 95% confidence interval: 1.33-2.72, p < .001; I2 = 53%). Subgroup analyses showed that the association between HP infection and PD-L1 expression in GC was not significantly affected by sample size, methods for PD-L1 evaluation and quality score (p for subgroup analyses all >.05). However, a stronger association was observed in studies with higher prevalence of HP infection (≥35%, OR: 2.58) as compared with those with lower prevalence (<35%, OR: 1.45, p for subgroup difference = .04).
Conclusion: Helicobacter pylori infection in GC patients is associated with tumour expression of PD-L1, suggesting HP infection may be a predictor of good response to immunotherapy in GC.
Keywords: Helicobacter pylori; gastric cancer; immunotherapy; meta-analysis; programmed death ligand-1.
© 2022 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.