Identification of the New Tumor Markers in Gastric Cancer by the Proteomic Approach

A significant proportion of at least 30% of patients had no chance to receive curative resection due to detection at late stage. To improve the survival of gastric cancer patients, a greater effort must be made to identify novel biomarkers for early diagnosis and more effective therapy. We have identified differentially expressed genes in gastric cancer tissues by means of cDNA microarray analysis. The results indicated SPARC (osteonectins), SLPI, and GRO1 possessed clinical significance among the highly upregulated genes in microarray analysis. In this new 3-year project, we will use the proteomics approach, ‘two-dimensional (2D) gel electrophoresis, and MALDI-TOF mass spectrometry’ to identify and isolate aberrantly expressed genes, which will be cloned, and characterized in order to find out new biomarkers. Proteomics provide powerful technology for analyzing the expression levels of thousands of proteins simultaneously both in normal and tumor tissues. With technological advances in protein separation and identification in this post-genomic era, large-scale comparative analysis of proteins in gastric cancer tissue and its matched normal mucosa might identify novel markers for gastric cancer. The cDNA from the clones will be sequenced and compared its identity in the gene bank. So far, several candidate proteins including CLIC1, GLO1, ARF1 and RAI have been chosen in the initial study for their highly expressing in the gastric carcinomas. The expression of the other aberrantly expressed genes will be scrutinized in the tissue samples of 80 gastric cancer patients using western blot analysis, immunohistochemistry and Q-real time RT-PCR. The cell functions will be examined after over-expressing or knock-down those proteins. In the past two year, we have performed validation and found a significant clinicopathological correlation of CLIC1 and GLO1 in gastric cancer patients. The results of CLIC1 have been published in this January’s “Prteomics”. In this project we intend to study other candidate proteins, GLO1, ARF1 and RAI for their highly expressing in the gastric carcinomas to determine whether the candidate genes are significant biomarkers for gastric cancer.

Project ID:PC9709-0945
External Project ID:NSC97-2314-B182-009-MY2