<p><b>OBJECTIVE</b>To
clone and identify
gastric cancer-related
genes and explore the possible pathogenic mechanism of
gastric cancer.</p><p><b>
METHODS</b>The differentially expressed
cDNA bands were isolated by fluorescent
mRNA differential display in
gastric cancer specimens, matched normal
gastric mucosa and premalignant lesions. The
motility-related protein-1 (MRP-1/CD9)
gene was one of the down-regulated
genes. MRP-1/CD9
gene expression in different kinds of gastric
tissue was analyzed by
Northern blot and
reverse transcription-
polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>MRP-1/CD9 expression was down-regulated in all
gastric cancer tissues.
Northern blot analysis confirmed this differential expression. RT-PCR
analysis showed that the MRP-1/CD9
gene expression was much lower in
gastric cancers(0.31+/-0.18) than in the matched normal gastric
tissue (0.49+/-0.24) and in the premalignant lesions (0.47+/-0.18) (P<0.05), and its expression in intestinal type
gastric cancer (0.38+/-0.16) was higher than that in diffuse type
gastric cancer (0.22+/-0.17) (P<0.05).</p><p><b>CONCLUSION</b>The MRP-1/CD9
gene expression was down-regulated in
gastric cancer, its expression was probably related to the
carcinogenesis and
histology types of
gastric cancer.</p>