Expression of copper-transporting P-type adenosine triphosphatase (ATP7B) as a prognostic factor in human endometrial carcinoma

Objective. Copper-transporting P-type adenosine triphosphate (ATP7B) has been reported to be associated with cisplatin resistance in vitro. However, the clinical significance of this transporter has not previously been addressed in endometrial carcinoma. Our goal was to investigate if ATP7B is expressed in endometrial carcinoma and whether its expression correlates with prognosis. Methods. We performed immunohistochemical analysis of ATP7B using a monoclonal antibody against ATP7B in 51 endometrial endometrioid adenocarcinomas. 27 of 51 patients were treated with cisplatin-based chemotherapy after surgery. Results. Cytoplasmic staining of tumor cells was observed in 37.3% (19/51 cases) of the analyzed carcinomas and no staining was observed in adjacent non-neoplastic cells. ATP7B positivity in the degree of differentiation of G2 and G3 carcinoma was significantly higher than that of G1 carcinoma (P = 0.019). The patients with ATP7B-positive tumors had a worse prognosis than that with ATP7B-negative tumors in overall survival and disease-free survival, respectively (P < 0.01). Conclusions. These findings suggest that overexpression of ATP7B expression in endometrial carcinoma is correlated with unfavorable clinical outcome in patients treated with cisplatin-based chemotherapy. ATP7B expression could be considered as a prognostic factor in patients with endometrial carcinoma.