Differential Expression of Motility-Related Protein-1 Gene in Gastric Cancer and Its Premalignant Lesions

OBJECTIVE To identify genes related to gastric cancer and to analyze their expression profiles in different gastric tissues.

METHODS The differentially expressed cDNA bands were assayed by fluorescent differential display from gastric cancer specimens, matched with normal gastric mucosa and premalignant lesions. The motility-related protein-1 (MRP-1/CD9) gene expression was studied by Northern blots and reverse transcription polymerase chain reaction (RT-PCR) in different kinds of gastric tissue

RESULTS A differentially expressed cDNA fragment showed lower expression in all gastric cancers compared to the normal gastric mucosa and premalignant lesions: and it was found to be homologous to the MRP-1/ CD9 gene. Northern blot analysis confirmed the differential expression. RT-PCR analysis showed that the MRP-1/CD9 gene was expressed at a much lower rate in gastric cancers (0.31 ±0.18) compared to the matched normal gastric tissue (0.49±0.24) and premalignant lesions (0.47±0.18)(P<0.05). Furthermore, its expression in intestinal-type of gastric cancer (0.38±0.16) was higher than that expressed in a diffuse-type of gastric cancer (0.22± 0.17)(P<0.05).

CONCLUSION The MRP-1/CD9 gene expression was down-regulated in gastric cancer and its expression may be related to the carcinogenic process and histological type of gastric cancer.