Decreased expression of DCC mRNA in gastric and colorectal cancer

The deleted-in-colorectal-cancer (DCC) gene, located on chromosome 18q 21.3, is considered to be a tumor suppressor gene related to cellular adhesion receptors. A loss of heterozygosity (LOH) on chromosome 18q is frequently observed in adenomatous polyposis coli, as well as in sporadic colon carcinoma and its liver metastatic loci. In this study, we investigated the expression of DCC mRNA in the resected specimens of 38 gastric cancers and 28 colorectal cancers by a reverse transcription-polymerase chain reaction method. In the gastric cancer patients, the mean expression level of DCC mRNA in the tumors was significantly lower than that in normal tissues (p = 0.009), but no difference was observed in the colorectal cancer patients. DCC mRNA expression was decreased in 15 gastric cancers (40%) and 10 colorectal cancers (36%), and there was a significant correlation between the decreased expression of DCC mRNA and nodal metastasis in colorectal cancer (chi 2 = 7.049, DF = 1, P = 0.0079). Two of four gastric cancer patients and none of seven colorectal cancer patients whose cancers were confined to the muscularis propria without metastasis showed decreased expression of DCC mRNA. These findings demonstrate that decreased expression of DCC mRNA may occur at an early stage in gastric cancer and at a late stage in colorectal cancer and that this decreased expression correlates with the potential to develop nodal metastasis.