Elevated expression of FGF7 protein is common in human gastric diseases

Growth alterations within the gastric mucosa during chronic gastric inflammation are key steps in gastric cancer development. FGF7, a specific mitogen for epithelial cells, is implicated in epithelial tissue repair and cancer. We investigated FGF7 expression in normal human stomach, and in 35 cases from various gastric pathologies including 23 gastritis and 8 adenocarcinoma cases. Modest FGF7 protein levels were detected in the normal mucosal gland epithelium and in stromal fibroblasts. FGF7 protein levels, however, were markedly increased in the mucosal epithelium of all gastric inflammation cases. A similar elevated expression was also observed in gastric adenocarcinoma. Upregulation of FGF7 protein was associated with a modest increase in FGF7 mRNA expression. Interestingly, high levels of FGF7 anti-sense (AS) RNA were observed in the gastric pathologies, at the same sites where FGF7 protein was upregulated. Altogether, these findings suggest a role for FGF7 in maintaining gastric mucosa integrity, and that FGF7 protein levels are regulated mainly by posttranscriptional mechanisms. The elevated FGF7 protein levels in gastric inflammation and gastric cancer, together with the known oncogenic potential of FGF7, implicate excessive FGF7 signaling in gastric tumorigenesis, and point to FGF7 as an attractive target for gastric cancer prevention and treatment.