Multiple studies have reported that chronic H pylori infection can interfere in the balance of HH pathway activity within gastric tissue.360H pylori may also contribute to gastric atrophy and intestinal metaplasia for increased potential of tumorigenesis.362 Mice with parietal cell-specific deletion of Shh were not observed to develop gastritis when infected by H pylori, and Shh in gastric mucosa was considered to act as a chemoattractant for macrophages.363. This evidence concerns the gene SHH and chronic atrophic gastritis.