Expression of the nm23 Gene in Primary & Metastatic Gastric Cancer Tissues

ABSTRACT

BACKGROUND: The nm23 gene was originally identified by screening of cDNA libraries from murine melanoma cell lines of varying metastatic potential. Gene expression of nm23 has been investigated in a number of tumors. Its down-regulation has been shown to be associated with metastasis or disease progression in some of the tumors. METHODS: We evaluated the nm23 mRNA levels in 23 surgically resected primary gastric cancers, in the matched adjacent mucosa, and in lymph nodes or distant metastatic foci by using Northern blot analyses and immunohistochemical staining. RESULTS: The expression of nm23 mRNA was lower in the matched normal adjacent mucosa than in the primary tumor. The expressions of the nm23 gene were higher in normal lymph nodes and in lymph nodes with metastasis than in primary tumors. This result was due to the high expression in normal lymph nodes. The expression of nm23 in distant metastatic foci was lower than it was in primary tumor tissues (p<0.05). The expression of the nm23 protein in a primary tumor with distant metastasis was higher than it was in a primary tumor with lymphnode metastasis only (p<0.05). CONCLUSIONS: It is suggested that down-regulation of the nm23 gene might have a role in distant metastasis in gastric cancer, possibly leading to a poor prognosis.