Gastric Cancer: ABO Blood Type

Human ABO blood type antigens exhibit alternative phenotypes and genetically derived glycoconjugate structures that are located on the red cell surface play an active role in the cells' physiology and pathology. ABO blood type has been known as a genetic factor which affects the development of gastric cancer. However, the mechanism is still uncertain. There is experimental evidence which suggests the role of ABO blood type in the infection of Helicobacter pylori (H. pylori). Molecular mimicry was shown with Lewis antigens, with which H. pylori can evade the host immune system. Blood group antigens were observed to act as an adhesion molecule onto which H. pylori attach. Nonsecretors compared with secretors lack "decoys"; therefore, nonsecretors are more vulnerable to intruders. These findings can be clues for future studies.