Study On The Differential Display Of Genes Related To Gastric Cancer And Its Premalignant Lesion

PURPOSEGastric cancer is one of the leading cause of death related to mal ignant neoplasia in the world. Many genetic alterations in gastric carcinogenesis have been clarified by biological molecular analyses recently, such as the activation of oncogenes and the inactivation of tumor suppressor genes.We used the fluorescent differential display technique to find differentially expressed genes among gastric cancer, its premalignant lesion and normal gastric tissue.It might be helpful to define molecular alterations in the gastric mucosa that may promote the development of gastric cancer. MATERIALS AND METHODSWe collected 4 gastric cancer tissues, 2 premalignant tissues and 4 normal tissues. Total RNA was isolated from each sample, and OD260 was tested respectively. Equivalent qualified RNA samples were added into DD-RT-PCR. 3 pairs of primers composed of 3 anchored primers with fluorescence and 1 arbitrary primer were used for amplification. PCR products were separated by sequencing gel electrophoresis, then differentially expressed genes were excised from the gel and re-amplified. They were sequenced after being cloned. Through BLAST software,the sequencing results were compared with GenBank database for homology analysis.RESULTS4 of the interesting cDNA fragments expressed higher in gastric cancer tissues than in normal and premalignant tissues. They were named Olft, 03ft, 12ft, 231ft. 2 bands , named 02ft and 04ft expressed higher in normal and premalignant tissues.BLAST analysis revealed that, Olft has the homologous of 99% with the gene known as SPTAN1. There was no identical sequence with 04ft, 12ft, 231ft in BLASTN database, but in querying GenBank EST, we found that they have high homologous with known sequences. 02ft and 03ft have extremely low sequence identity with any genes from GenBank and sequences from EST database. The sequence data was submitted to dbEST with accession No.BM890598 and BM890599. CONCLUSIONSWe found six differentially expressed genes. They might be involved in the gastric carcinogenesis.1. Four have high homologous with known genes, of which one was SPTAN1.2. Tow have no evident homologous with known genes, which might be novel gene fragments.