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

Gastric cancer (GC) is one of the most common malignancies worldwide, and Helicobacter pylori (HP) infection is a well-established risk factor for its development. Programmed death-ligand 1 (PD-L1) expression is a crucial biomarker for predicting the efficacy of immune checkpoint inhibitors in cancer treatment. While HP infection and PD-L1 expression in GC may be linked, the relationship between them remains unclear, in part because there have been conflicting results reported from various studies.

To perform a meta-analysis to assess the relationship between HP and PD-L1 expression in patients with GC.

A systematic literature review was conducted using PubMed, Embase, Cochrane Library, and Web of Science databases. Observational studies that examined the association between HP infection and PD-L1 expression in patients with GC were included. Odds ratios and 95% confidence intervals were calculated to estimate the association. Heterogeneity was assessed using Cochrane's Q test and I² statistic. A random-effects model was used due to significant heterogeneity across studies.

Fourteen studies involving a total of 3069 patients with GC were included. The pooled analysis showed a significant association between HP infection and increased PD-L1 expression in GC tissues (odd ratio = 1.69, 95% confidence interval: 1.24-2.29, P < 0.001, I ² = 59%). Sensitivity analyses confirmed the robustness of these findings. Subgroup analyses did not show significant variation based on geographic region, sample size, or method of PD-L1 assessment. Publication bias was minimal, as shown by funnel plots and Egger's regression test.

HP infection is associated with increased PD-L1 expression in GC, suggesting that HP status may influence the response to programmed cell death protein 1/PD-L1 blockade therapy.