Emerging evidence suggests that the efficacy of immunotherapy in patients with advanced HER2-negative gastric cancer differs between Asian and non-Asian populations. This review examines potential factors contributing to these disparities, including differences in demographic and clinicopathologic characteristics, somatic mutations, molecular subtypes, tumor immunity, Helicobacter pylori (H. pylori) infection, dietary habits, and gut microbiome composition. These factors may serve as predictors of immunotherapy response in gastric cancer patients. For example, the prevalence of molecular subtypes and somatic mutations have been linked to variations in immunotherapy efficacy between Asian and non-Asian populations. In addition, differences in H. pylori infection rates, dietary habits, and gut microbiota composition may influence systemic immune responses, and consequently, immunotherapy outcomes. Understanding the factors contributing to these disparities in immunotherapy response is crucial for optimizing treatment strategies and improving outcomes for patients with gastric cancer. Further research into the mechanisms underlying racial and ethnic disparities in immunotherapy response is needed to identify potential biomarkers predictive of immunotherapy response in diverse patient populations.
Zhao et al. (2026) studied this question.