Expression of nm23-H1 and nm23-H2 proteins in prostate carcinoma

The nm23 gene products/nucleoside diphosphate (NDP) kinase expression in prostate carcinomas and benign hyperplasias was evaluated immunohistochemically. Monoclonal antibodies against nm23-H1 and nm23-H2 proteins were prepared using the corresponding proteins fused with glutathione S-transferase as immunogens. Of the 80 cases of nonmetastatic prostate carcinoma examined, 74% (59/80) and 60% (48/80) were immunoreactive for nm23-H1 or nm23-H2 protein, respectively. Negative staining for nm23-H1 occurred in 83% of metastatic lesions, while 34% were negative for nm23-H2. All primary tumors corresponding to the metastases examined showed positive immunostaining for nm23-H1, indicating an inverse relationship between expression of this protein and metastatic status. nm23-H2 protein was detected in 83% of primary tumors and its expression appeared to be significantly correlated to the degree of histological differentiation. In contrast, all cases of benign prostatic hyperplasia showed elevated levels of both nm23-H1 and nm23-H2 expression. These data suggest that the nm23/NDP kinase may play a role in suppressing the expression of malignant potential in prostate carcinomas.