A novel mechanism for inflammation-associated carcinogenesis; an important role of activation-induced cytidine deaminase (AID) in mutation induction.

Inflammation is a risk for cancer development; however, its mechanism is unknown. Recent studies have revealed that activation-induced cytidine deaminase (AID), which plays essential roles in both class-switch recombination and somatic hypermutation of immunoglobulin gene in B lymphocytes, is aberrantly expressed in non-lymphoid cells not only by H.pylori and HCV infection but also by various proinflammatory cytokines, leading to the generation of gene mutations. These findings not only suggested a new mechanism of inflammation-associated carcinogenesis but has also opened up a new field of tumor biology.