BACKGROUND/AIMS: Aminopeptidase N (APN)/CD13 is a transmembrane ectoenzyme occurring in a wide variety of cells. Recently, APN/CD13 has been reported to be involved in tumor invasion and metastasis. However, precise functions in tumor cells, and its role in gastric carcinoma remain unclear.

METHODOLOGY

To evaluate the role of APN/CD13 in gastric carcinoma, we conducted immunohistochemical staining for APN/CD13 in 121 gastric carcinoma specimens, using anti-APN monoclonal antibody. The relationship between APN/CD13 expression and various prognostic factors of gastric carcinoma were investigated.

RESULTS

Of the 121 patients with gastric carcinoma studied, 48 were strongly positive, 36 were weakly positive, and 37 were negative. Overall survival rate of the patients with negative APN/CD13 expression was significantly lower than that of the patients with positive APN/CD13 expression. APN/CD13 expression was negatively associated with lymph node metastasis. Multivariate analysis showed APN/CD13 expression to be a significant prognostic factor.

CONCLUSIONS

Decreased expression of APN/CD13 was associated with a poor prognosis. Hence, our results demonstrate that the immunohistochemical detection of APN/CD13 could provide useful information as one of the prognostic factors in gastric cancer.