As we found that the CLDN-4 high-expression group showed more differentiated-type histology and intestinal-type EGC, we hypothesized that high expressions of CLDN-4 could be linked to a wide range of precancerous lesions, such as atrophic gastritis, which may contribute to the differentiated-type histology, intestinal-type EGC, and predominant synchronous tumors. Here, CLDN4 is linked to chronic atrophic gastritis.