A novel gene,GCRG224,is differentially expressed in human gastric mucosa

摘要

AIM: To clone genes that may predispose us to humangastric cancer and to analyze it's expression in gastric tissues.METHODS: Specimens of paired tumor, paratumor andnormal gastric mucosa tissues collected from fifteen patientswho suffered from stomach antrum adenocarcinoma wereused for analysis. Seven out of the fifteen cases were firststudied by fluorescent differential display reversetranscription polymerase chain reaction (DDTR-PCR) analysis.The differentially expressed bands of interest were cloned,analyzed by Northern blot, sequencing and RT-PCR. ThroughBLAST, the sequencing results were compared with GenBankdatabase for homology analysis. In situ hybridization withDIG-labeled cRNA probes was used toanalyze the expressionof interesting cDNA bands in paraffin embedded pairednormal gastric mucosa and cancer tissues isolated from 30gastric adenocarcinoma patients.RESULTS: DDRT-PCR showed that one of the interestingcDNA bands, which was named W2, expressed much higherin all seven tested tumor and paratumor samples than intheir normal counterparts, it was sub-cloned into a pGEM-TEasy vector. Two subclones were subsequently obtained.One of the subclone, GCRG224, was studied further. Thesequencing result showed that GCRG224 consisted of 1 159base pairs and had one open reading frame (ORF). It locatedat human chromosome 11q14. No homologue was found inGenBank database with GCRG224-ORF. This nucleotidesequence data were submitted to GenBank with accessionNo. AF438406. RT-PCR showed that GCRG224 expressedhigher in 11/15 gastric cancer tissues than in non-tumortissues. However, the result of Northern blot analysis showeda higher GCRG224 expression in the non-tumor tissue thanin the tumor one. Human multiple tissue Northern blot analysisrevealed that GCRG224 also expressed in human normal colontissue, and peripheral blood leukocyte. In situ hybridizationanalysis showed that only 5/30 adenocarcinoma, 3/18dysplasia and 6/18 intestinal metaplasia showed higherGCRG224 expression level than the normal gastric glands.However, GCRG224 was over-expressed predominantly in 26/30 cases of normal mucosal epithelium.CONCLUSION: A novel gene named GCRG224 wasidentified from human gastric mucosal tissue. Itoverexpressed in almost all gastric mucos al epithelium butonly a small portion of cancer and precancerous leisions.The role of GCRG224 expression in gastric epithelium needsfurther study.