The paradox of Helicobacter pylori: how does H. pylori infection protect against esophageal cancer?

Helicobacter pylori is a microaerophilic gram-negative bacterium infecting around half of the world's population. Despite its well-known role in gastric malignancies, its impact on esophageal cancer comes with a complex paradox. Several mechanisms have been proposed to explain its observed lack of carcinogenic activity in the esophagus, including the trigger of anti-inflammatory pathways, promoting atrophic gastritis, and esophageal microbiome modulation. However, recent studies have highlighted a significantly more complicated interplay, where H. pylori, typically considered a pathogen, may even deliver a protective effect against esophageal carcinogenesis. This paper aims to evaluate the prevalence of H. pylori infection among patients with esophageal carcinoma, discussing the underlying mechanisms of the paradoxical effects of H. pylori on esophageal cancer.