Isolation of two novel genes, down-regulated in gastric cancer

Using a differential display technique, we identified two genes that are down-regulated in human gastric cancer tissue as compared to normal gastric mucosa. The down-regulated expression of these genes in gastric cancer tissue was confirmed by northern blotting analysis and RT-PCR. One, CA11, was a novel gene expressed predominantly in the stomach and was depleted in all of the gastric cancer cell lines examined. The other gene, GC36, was homologous to the digestive tract-specific calpain gene, nCL-4. The expression of both GC36 and nCL-4 was suppressed or depleted in gastric cancer cell lines of differentiated and poorly differentiated types. This is the first report of genes, the expression of which is down-regulated with considerable frequency in gastric cancer.