HP and chronic gastritis: A relationship between H. pylori and IRX1 was observed by Guo and colleagues [88], who identified that the levels of IRX1 promoter methylation in tissue DNA from Hp+ chronic gastritis were higher than observed in Hp- chronic gastritis tissues, 55.30% ± 13.17 versus 5.20% ± 6.31, respectively (p < 0.01).