Spontaneous development of gastrointestinal neoplasms in cagA-Tg mice in the absence of infiltrating immune cells indicates that prolonged CagA expression is sufficient for carcinogenesis in this particular transgenic system.157 This suggests that inflammatory responses are not indispensable for CagA-induced gastrointestinal carcinogenesis, which may depend on mutual feedforward augmentation of the five malfunctional biological processes in CagA-expressing cells. This evidence concerns the gene S100A8 and digestive system neoplasm.