Copper-transporting P-type adenosine triphosphatase (ATP7B) is expressed in human gastric carcinoma

This study describes the first report that a copper-transporting P-type adenosine triphosphatase, ATP7B, is expressed in human gastric carcinomas. Herein, we investigated the hypothesis that ATP7B, which was shown to be associated with cisplatin resistance in vitro, is expressed in certain gastric carcinomas. To test this hypothesis, ATP7B expression level was examined in 51 gastric carcinomas by immunohistochemistry. ATP7B protein could be detected in 41.2% (21/51) of gastric carcinoma by immunohistochemical analysis. In ATP7B-positive tumors, adjacent non-neoplastic tissue was similarly analyzed, revealing that ATP7B is upregulated in gastric carcinoma. ATP7B expression in poorly differentiated/undifferentiated carcinoma was significantly higher than that in well/moderately-differentiated carcinoma (P=0.0278). These findings suggested that ATP7B expression might be a chemoresistance marker against cisplatin in some patients with poorly differentiated/undifferentiated gastric carcinoma.