Helicobacter pylori

Helicobacter pylori (HP) is a spiral rod-shaped gram-negative bacterium, which is classified as Class I carcinogen by WHO. HP has the unique ability to produce urease, which can convert urea into ammonia to alkalize the stomach acidic environment, and then it parasitizes the gastric mucosa surface and destroys the mucosal barrier, ultimately leading to inflammation and even carcinogenesis. In clinical practice, HP is mainly used to diagnose gastric cancer, and it is closely related to the occurrence and development of tumors. Some research found that HP can silence tumor suppressor genes by abnormal methylation, induce oxidative stress damage by up-regulating NOX4 expression, maintain bacterial survival by promoting FGFR4 and NRF2 production, and mediate epithelial-mesenchymal transition (EMT) by activating the JAK2/STAT3 pathway. Meanwhile, HP can regulate FHIT and RASSF1A to trigger uncontrolled proliferation in laryngeal cancer, synthesize toxic factor CagA to inhibit cell autophagy in cholangiocarcinoma, and express inflammatory factors and activate the NF-κB pathway to form inflammatory microenvironment in colorectal cancer.