In order to establish warning system of gastric cancer, using cell line GC7901 and GES-1 as targets,8 cDNAs of differentially expressed genes between them were isolated by mRNA differential display,and then respectively named as GCYS-1 to GCYS-7,GCYS-20,and then were cloned into pGEM-T vector. These cDNA fragments were up-regulated in GC7901 and down-regulated in GES-1 as shown by Northern blot.DNA sequencing demonstrated that all of them were novel.These sequences have been assigned the database accession numbers in GenBank as below:AF054162,AF054163,AF054164,AF054165,AF054166,AF054167,AF054168,AF219140.