TLR9 and neoplasm: The first study that introduced the role of TLRs in tumour angiogenesis was conducted on H .pylori–associated gastric cancer, in which it has shown that H .pylori–induced cyclooxygenase‐2 (COX‐2) and prostaglandin E2 (PGE2) expression enhanced tumour angiogenesis via interacting with TLR2 and TLR9.60