The chemokine receptor CCR7 is expressed on epithelium of non‐inflamed gastric mucosa, Helicobacter pylori gastritis, gastric carcinoma and its precursor lesions and up‐regulated by H. pylori
CCR7 chemokine‐receptor expression on tumour cells of gastric carcinoma has been associated with lymph‐node metastasis and is thought to play an important role in metastasis. However, so far it is unknown whether CCR7 is newly up‐regulated on gastric carcinoma or already expressed in non‐neoplastic gastric epithelium. Therefore, epithelial CCR7 expression was investigated in the process of gastric carcinogenesis: non‐inflamed mucosa –Helicobacter pylori gastritis – intestinal metaplasia/dysplasia – gastric carcinoma. CCR7 was expressed by gastric epithelium in non‐inflamed gastric mucosa (n = 5), H. pylori gastritis (n = 17), intestinal metaplasia (n = 10), dysplasia (n = 3) and on tumour cells in 20 of 24 patients with gastric carcinoma (13/14 intestinal‐type; 7/10 diffuse‐type) as tested by immunohistochemistry. As CCR7 expression by gastric epithelium was significantly stronger in H. pylori gastritis than in non‐infected mucosa, the influence of H. pylori on CCR7 receptor expression of gastric epithelial cells was investigated by fluorescence activated cell sorter analysis. H. pylori strains up‐regulated the CCR7 chemokine‐receptor in CCR7‐positive cell lines. No difference in CCR7 up‐regulation between cag+ and cag–H. pylori strains was found. Epithelial CCR7 up‐regulation by H. pylori may alter the metastatic fate of gastric carcinoma. Additionally, CCR7 expression not only on gastric carcinoma, but also on non‐neoplastic gastric epithelium, suggests a novel biological function.