NM23 EXPRESSION IN HUMAN GASTRIC CANCERS - POSSIBLE CORRELATION OF NM23 WITH LYMPH-NODE METASTASIS

In order to elucidate the relationship between nm23 and metastasis in human gastric cancers, we analyzed gene and protein expression of nm23-H1 using Northern blot and immunohistochemical techniques. nm23-H1 gene expression was identified in 17 out of 19 gastric cancer tissues. The signals in the tumor tissues presenting regional lymph node metastasis seem to be lower than those in the tumor tissues without regional lymph node metastasis, suggesting a role of nm23-H1 in the regional lymph node metastasis in the gastric cancers. However, the protein expression detected immunohistochemically was not correlated to the gene expression, partly because of difficulty in quantifying the amount of protein. Expression of the nm23-H1 gene as well as the nm23-H1 protein in the tumor tissues was higher than those in the corresponding normal mucosae. This suggests a linkage of nm23-H1 in the process of the gastric cancer progression. We also analyzed the sequence abnormalities of the nm23-H1 gene in the gastric cancer tissues using a direct sequencing technique, no mutations were observed.