Effects and mechanisms of Helicobacter pylori infection on the occurrence of extra-gastric tumors

Abstract

Helicobacter pylori (H. pylori) colonizes the human stomach and many studies have discussed the mechanisms of H. pylori infection leading to gastric diseases, including gastric cancer. Additionally, increasing data have shown that the infection of H. pylori may contribute to the development of extra-gastric diseases and tumors. Inflammation, systemic immune responses, microbiome disorders, and hypergastrinemia caused by H. pylori infection are associated with many extra-gastric malignancies. This review highlights recent discoveries; discusses the relationship between H. pylori and various extra-gastric tumors, such as colorectal cancer, lung cancer, cholangiocarcinoma, and gallbladder carcinoma; and explores the mechanisms of extra-gastric carcinogenesis by H. pylori. Overall, these findings refine our understanding of the pathogenic processes of H. pylori, provide guidance for the clinical treatment and management of H. pylori-related extra-gastric tumors, and help improve prognosis.

Keywords: Extra-gastric tumors; Gut microbiome; Helicobacter pylori; Immune system response; Mucosal barrier.

Figure 1

Summary schematic of the effects and mechanisms of Helicobacter pylori infection on the occurrence of extra-gastric tumors. The orange indicates that Helicobacter pylori infection has a promoting effect on cancer progression and occurrence, the gray indicates no significant effect on cancer progression and occurrence, and the blue indicates an inhibiting effect on cancer progression and occurrence. HCC: Hepatocellular carcinoma; HBV: Hepatitis B virus; HCV: Hepatitis C virus; CCA: Cholangiocarcinoma; GBC: Gallbladder carcinoma; CRC: Colorectal cancer; H. pylori: Helicobacter pylori; Hpn: Histidine-rich protein; CagA: Cytotoxin-associated gene A.